 RAVI MOHAN MISHRA

## [Query] Time and Work

Query) Three men A,B,C working together can do a job in 6 hours less time than A alone, in 1 hour less time than B alone, and one one half the time needed by C when working alone. Then A and B can together do the job in

a) 2/3 hours
b) 3/4 hours
c) 3/2 hours
d) 4/3 hours

Solution

Assume A,B & C complete the work in x days,y days and z days.

A,B,C can complete the work in 6 hours earlier than A alone.

1/x + 1/y + 1/ z = 1/(x-6) --------- (1)

A,B,C can complete the work in 1 hours earlier than B alone.

1/x + 1/y + 1/ z= 1/(y-1) ---------- (2)

A,B,C can complete the work in half the time than C alone.

1/x + 1/y + 1/ z= 2/z ---------------(3)

For calculating TIME taken by A and B to complete the working together we have to calculate
Work done by A and B together in 1 day = 1/x + 1/y

from Equation (3) we get 1/x + 1/y = 1/z --- (4) => We need to calculate value of z for getting the answer.

Comparing Equations (1) and (3) we get

1/(x-6) = 2/z
=>         z= 2(x-6)
=>         x = 6+z/2

Comparing Equations (2) and (3) we get

1/(y-1) = 2/z
=> 2(y-1) = z
=>         y = z/2 + 1

Putting the values of x and y in Equation (4) we get

=> 1/(6+z/2) + 1/(1+z/2) = 1/z

=>  2/(12+z) + 2/(2+z) = 1/z -------- (5)

=> 2[ (2+z)+(12+z) ] = 1/z [ (12+z)(2+z) ]

=> 2z [ 14+2z ] =  24+z^2 + 14 z

=> 3z^2 + 14z - 24 = 0

=> 3z^2 + 18z - 4z -24 =0

=> (3z-4) (z+6) = 0

=> z = 4/3  ; z= -6 (rejected)

It means 1/x + 1/y = 1/(4/3) => A and B will take 4/3 hours to complete the work.

Hence option [d] is correct.

Shortcut: You can calculate value of z by checking the options. Only z=4/3 will satisfy the equation no (6).
Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. ## Free Webinar: How To Master Data Interpretation for Bank PO:Register to Attend

Date: 29th March 2015 (Sunday)
Time: 10:00 PM - 11:30 PM (IST)

Many aspirant has sent me emails asking strategies to be followed for preparing Data Interpretation for scoring better marks in DI. This session will highlight key focus areas for mastering Data Interpretation.

Register below to get an invite of the session.The invitation will be sent based on first come first serve in case registrations cross the threshold.

Invitation with webinar link will be emailed to you by 27th February.
Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. ## [IBPS PO Interview Experience] Subhankar shares his IBPS PO interview Experience

IBPS PO 29th Jan 2014(Panel 5 afternoon slot)
Subhankar (Baban) Basak

I got 13 again!! :) :)

Not a lucky guy ..I suppose!! Well I cracked my forehead when I was 4 years old so..no luck for me only work.

Panel members M1,M2,M3,M4 and F1
M1: while entering.. u r from Siliguri
Me: yes sir!!

I wished them good evening and was asked to sit..I said thank you then (sat straight hands on knees..)

M1. So Siliguri is famous for Teas..
Me: Yes sir.. four T’s?

M1: (question mark on face!!)
Me: Sir Tea, Transport , Timber and Tourism..and TT(table tennis) also (me smiling)

M1: good good! What is your qualification?(smiling now)
Me: Sir I did MBA on Finance after my Btech on CSE.

M1: So when did you passed MBA?
Me: 2012

M1: then after that you started preparing for banking?
(He got my experience certificates in front of him)
Me: No Sir, I worked with two companies after MBA then told about my after MBA job experience in brief.

M1: Okay. Have you heard about CASA?
Me: yes sir!

M1: take a scenario where CASA deposits is 60% for a bank and rest are other deposits. Is it good or bad!
Me: (After 2 secs)..its Good sir!

M1: Why?
Me: Because CASA is the backbone of any bank and interest to be paid on CASA is minimal as compared to FDs and rDs..so the interest to be earned from it by giving loan is more!! Thus More CASA percentage is good news :-)

M1: Good.. You know BEP?
Me: after trying to define it through investment and return on investment failed and said..sir Its no profit no loss point!!

M1: (quizzical to satisfied look) that’s what I wanted to know!
(He refers to me M2)

M2: So what is your specialization?
Me: Sir Majored in Finance and Systems minor!

M2: Okay..what is Market?
Me : answered..

M2: types of market?
Me: Sir, not clear I could not understand the question market for?

M2: What is market type?
Me: Sir are you asking about Primary or secondary market or on what factors market can be segmented?(I started to confuse).

M2: you answer the best you understood the question..
Me: tried to explain that product based markets can be classified depending on the target profile of the product: age, gender, demographic, income capacity..blah blah!! (He didn’t looked much satisfied) again Primary market and secondary market for Shares answered..(no reaction. I left it over there..)

M2: what is Monopoly market?
Me: (I started defining oligopoly in tension, got a puzzled look..stopped, apologized sorry sir I got confused)..sir only one producer and no competitor eg: Indian railways!!(me smiling now) Okay..sir I got it you wanted to know about Oligopoly , mono poly and those markets!! (I started to smile)

M2:( he was smiling now)
Me: Sir not an economics background guy am sorry sir, I couldn’t understand it in the first time..
M2: (refers me to M3)

M3: How many type of loans are there?
Me: Sir..many types: educational, home, personal, corporate, agricultural etc. sir cant remember all smiling

M3: what is IRR?
Me : Answered he was satisfied.

M3: NPV or IRR which one is better. Me NPV!! Clarified.( He looked satisfied!)

M3: who is chief economic adviser of World Bank?
Me: (I could not recall Kaushik Basu’s name) I said..sir the President is Jim Yong Kim.. cant recall the chief eco adviser.

M3: No, not the president the adviser!
Me: Sir I don’t know sir!!

M4: SHG?
Me: replied.

M4: again asked an abbreviation ( I never heard can’t remember now).
Me : Sir I don’t know sir!

F1: What is green channel?
Me : Maam I don’t know !

F1. Okay.. what is risk?
Me : replied. She was satisfied.

F1: types of risk?
Me : replied..

F1: Wat is market risk?
Me: replied with example :-)

F1: wat is CAPM?
Me: replied.

F1: Do u remember the formulae?
Me: Maam I am not sure perhaps it is E=Rf+beta(Rm-Rf). Need to ckeck with the position of rm and rf .(checked I was right back home :P)
F1 : Okay! (nods to m1)

M1: Tell me something about your family.
Me: Sir, only son of y fathers name and my mothers name.

M1: Fathers profession?
Me: told! (He nodded!)

M1 : What is MIS?
Me: I told the full form and explained in brief..(I could do better than that ) cited an example.

M1: Is it important in banks?
Me: Absolutely yes sir!! Connecting the lower tier with the top level management managing, planning and controlling towards achievement of objectives is the primary goal! So MIS plays an important role in decision making and thus helps bank to focus more on delivering the quality of service.(blah blah blah blah..hahahahaha)

M1: So you have work experience..what do you want to bring in a bank?
Me: replied with a prepared answer..(why shall we take you)

M1: Thank you !!
Me: I thanked all and left!! (forgot to wish them on way back!)

( I really appreciate Subhankar for sharing his detailed Interview Experience.It works as beacon for future aspirants.)

for more interview Experiences click below:
IBPS PO Interview Experience
Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. ## [IBPS PO Interview] Share your IBPS PO Interview Experience for benefit of Future Aspirants

Hope all of you are doing well in your IBPS PO interview. Please share your IBPS PO interview experience in comment box for reference of future aspirants.Try to include as much information as you can remember so that aspirants get a complete picture of the Interview.

Provide your Interview Experience in below format:

Name:
Graduation Stream:
Date of Interview:
Venue:
No of Board Members:
Interview Experience:  ( Include as much questions as you can remember )

#### Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. ## [Aptitude] Calculation : How to Calculate square upto 75 in 5 seconds?

In my previous article How to Calculate Squares (25-125) quickly, i discussed few shortcuts to calculate squares.In this article you will learn another method which can provide you square up to 75 more quickly (in 5 seconds).

To calculate squares up to 75 quickly. You need to mug up squares up to 25( ratta laga lo) .

Note: For calculating squares up to 75 quickly. You must remember square upto 25.

Let us make a table of squares up to 25 for your convenience.

 Number Square Number Square 1 1 13 169 2 4 14 196 3 9 15 225 4 16 16 256 5 25 17 289 6 36 18 324 7 49 19 361 8 64 20 400 9 81 21 441 10 100 22 484 11 121 23 529 12 144 24 576 25 625

Approach

Step1: Difference of number from 25 will be the first two digits of the square.

Step2: Take difference from 50 => whatever value you get , square it => will give you last two digits. If square is having three digits, consider last two digits and remaining digit will be forwarded as a carry.

Note: Squares of 1,2,3 will have only one digit. So, you need to write the corresponding squares as 01,04,09.

Step3: If there is a carry from Step2, add it to the value you got in step1, this will be final first two digits of square.

Summary: Above steps may look bit confusing,Don't worry if you did not get it.I will make it clear to you through examples.

Get ready for colorful explanation of the above steps :)

### CASE 1: When there is no carry in Step2

Example 1: Calculate Square of 44?

Solution:
Step1: First two digits = Difference from 25 = 19
Step2: Last two digits = (Difference from 50 )^2 = (6)^2 = 36
Step3: No need of step 3. Since there is no carry from step 1.

Final Answer,  (44)^2 = 1936

Example 2: Calculate Square of 58?

Solution:
Step1: First two digits = Difference from 25 =33
Step2: Last two digits = (Difference from 50 )^2 = (8)^2 = 64
Step3: No need of step 3. Since there is no carry from step 1.

Final Answer,  (58)^2 = 3364

Example 3: Calculate Square of 49?

Solution:
Step1: First two digits = Difference from 25 =24
Step2: Last two digits = (Difference from 50 )^2 = (1)^2 = 01
Step3: No need of step 3. Since there is no carry from step 1.

Final Answer,  (49)^2 = 2401

Example 4: Calculate Square of 51?

Solution:
Step1: First two digits = Difference from 25 =26
Step2: Last two digits = (Difference from 50 )^2 = (1)^2 = 01
Step3: No need of step 3. Since there is no carry from step 1.

Final Answer, (49)^2 = 2601

Example 5: Calculate Square of 47?

Solution:
Step1: First two digits = Difference from 25 =22
Step2: Last two digits = (Difference from 50 )^2 = (3)^2 = 09
Step3: No need of step 3. Since there is no carry from step 1.

Final Answer, (47)^2 = 2209

### CASE 2: When there is no carry in Step2

Example 6: Calculate Square of 29?

Solution:
Step1: First two digits = Difference from 25 =4
Step2: Last two digits = (Difference from 50 )^2 = (21)^2 = 441
Last two digits = 41 & Carry=4

Step3: Updated First two digits = 4 + Carry = 4 + 4 = 8

Final Answer,  (29)^2 = 841

Example 7: Calculate Square of 34?

Solution
Step1: First two digits = Difference from 25 =9
Step2: Last two digits = (Difference from 50 )^2 = (16)^2 = 256
Last two digits = 56 & Carry=2

Step3: Updated First two digits = 9 + Carry = 9 + 2 = 11

Final Answer, (34)^2 = 1156

Example 8: Calculate Square of 68?

Solution:
Step1: First two digits = Difference from 25 =43
Step2: Last two digits = (Difference from 50 )^2 = (18)^2 = 324
Last two digits = 24 & Carry=3

Step3: Updated First two digits = 43 + Carry = 43 + 3 = 46

Final Answer, (68)^2 = 4624

Example 9: Calculate Square of 28?

Solution:
Step1: First two digits = Difference from 25 =3
Step2: Last two digits = (Difference from 50 )^2 = (22)^2 = 484
Last two digits = 84 & Carry=4

Step3: Updated First two digits = 3 + Carry = 3 + 4 = 7

Final Answer, (28)^2 = 784

Example 10: Calculate Square of 74?

Solution:
Step1: First two digits = Difference from 25 =49
Step2: Last two digits = (Difference from 50 )^2 = (24)^2 = 576
Last two digits = 76 & Carry=5

Step3: Updated First two digits = 49 + Carry = 49 + 5 = 54

Final Answer, (74)^2 = 5476

Example 11: Calculate Square of 39?

Solution:
Step1: First two digits = Difference from 25 =14
Step2: Last two digits = (Difference from 50 )^2 = (11)^2 = 121
Last two digits = 21 & Carry=1

Step3: Updated First two digits = 14 + Carry = 14 + 1 = 15

Final Answer,  (39)^2 = 1521

Note:I have shown above examples step by step to explain the approach. All these steps can be done mentally. If you follow above approach and practice a bit you can calculate square upto 75 in 5 seconds without using pen & paper.

Mock Questions

Q1] Calculate square of 31.

A] 961
B] 1061
C] 931
D] None

Q2] Calculate square of 34.

A] 1056
B] 1156
C] 1136
D] None

Q3] Calculate square of 42.

A] 1664
B] 1764
C] 1864
D] None

Q4] Calculate square of 54.

A] 2806
B] 2816
C] 2916
D] None

Q5] Calculate square of 59.

A] 3381
B] 3481
C] 3581
D] None

Q6] Calculate square of 72.

A] 5184
B] 5284
C] 5084
D] None

Q7] Calculate square of 64.

A] 3996
B] 4096
C] 4196
D] None

Q8] Calculate square of 67.

A] 4289
B] 4389
C] 4489
D] None

Do provide your valuable feedback & suggestion in comment box.
Good Luck :)

If you find this article useful, do share it.

Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. ## [DI-4] Query: Data Interpretation : How to Calculate Highest Percentage Growth?

Received Below Query By email:

Query: Shortcut approach for below question:

Above Table shows Income of Six different persons in different years. All amounts given in table are in Lacks.

Question: In 2002, who among the following has the highest percentage growth in income.

a) Harish
b)Indira
c)Kiran
d) Lalit
e)Manish

For calculating such questions faster we need to have some knowledge of ratios, First I will discuss few properties of ratio which are helpful while comparing ratios then you will be able to solve this question quickly.

Following cases may arise while comparing ratios:

Case 1) If numerator is different and Denominator is kept same

Example: Compare 81/234 and 87/234

If you look at both fractions you will find denominator same and 87 > 81
so , 87/234 will have higher value than 81/234.

Note: If denominator is same ; the fraction which have greater value of numerator will be greater in Value.

Case 2) If numerator is same and Denominator is Different.

Example:Compare 81/234 and 81/239

If you look at both fractions you will find Numerator same and denominator different. The fraction having smaller denominator value will have higher value.

Hence , 81/234 will have higher value than 81/239.

Note: If numerator is same ; the fraction which have smaller value of denominator will be greater in Value.

Case 3) Numerator is increased and Denominator is decreased.

Example: Compare 81/234 and 85/233.
Obviously 85/233 will be greater than 81/233.

Note: When Numerator is increased and Denominator is decreased the resultant fraction will have higher value than original one.

Case 4) Numerator is decreased and denominator is Increased

Example: Compare 81/234 and 75/295
Obviously 81/234 is larger than 75/295.

Note: When Numerator is Decreased and Denominator is increased the resultant fraction will have smaller value than original one.

Case 5) When both Numerator and Denominator is increased/ Decreased.

In this particular case it becomes difficult to judge which number is greater or smaller just by looking at fraction. Here it is better to find M.F. of  Numerator and M.F. of denominator to know which fraction is larger.

If M.F. of Numerator > M.F. of denominator  ==> 2nd fraction will be greater.
If M.F. of Numerator < M.F. of denominator  ==> 2nd fraction will be smaller.
If M.F. of Numerator = M.F. of denominator  ==> 2nd fraction will be equal to 1st fraction.

Now lets get back to Original Question:

Question: In 2002, who among the following has the highest percentage growth in income.

a) Harish
b)Indira
c)Kiran
d) Lalit
e)Manish

Solution:

In my previous posts I have discussed whenever you have to calculate Percentage growth, you have to calculate Multiplying Factor.

Read: How to Calculate Percentage Growth?

Since we have to calculate percentage increase in 2002 ( base year = 2001 )

M.F. =  Income in 2002/ Income in 2001

HARISH: M.F. = 1.5 / 1.44    = 1 + 0.06/1.44
INDIRA: M.F.  =  1.56 / 1.45 = 1 + 0.11/1.45
KIRAN:  M.F.  = 1.74/1.68    = 1 + 0.06/1.68
LALIT:   M.F   = 1.92 / 1.80  = 1+ 0.12/1.80
MANISH: M.F. = 2.61 / 2.5   = 1 + 0.11/2.5

Here we need not to calculate percentage growth for everyone , we just have to compare them and tell who is highest.

Highest percentage growth means Highest Multiplying Factor.

So we have to find highest Multiplying factor.

Now compare Harish(0.06/1.44)  and Kiran(0.06/1.68)

Numerator same => The one having smaller denominator will have larger value.
So , Between Harish and Kiran => Harish has high growth rate.

Now compare Harish(0.06/1.44)  and Indira(0.11/1.45)

Denominator and numerator both have increased.
M.F. of Numerator ~ 2 ( Numerator approximately doubled )
while denominator is changing by very small amount.
=> M.F. of Numerator > M.F. of denominator
so, 0.11 /1.45 > 0.06/1.44
So, growth rate of Indira is more than growth rate of Harish.

Now compare Indira(0.11/1.45) and Lalit(0.12/1.80) and Manish(0.11/2.5)

Here numerators are almost same for everyone and there is lot of variation in denominator.
So, the fraction having smallest denominator will be largest.

So, Indira(0.11/1.45) is having Highest Percentage Growth.

Hence option[B] Indira is correct.

Practice above mentioned approach as much as you can,It will definitely save your time during exam,In many questions you will be able to mark the answer just by looking at the table:)

Good Luck :)

Do provide your feedback in the comment Box.

Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. ## [Average-2] Change in Average due to entry/exit of One Element.

Ques1: Average age of a class of 20 students is 20 years. When teachers' age is also included average of entire class  increases by 1.Calculate the age of teacher?

Ques2: Average age of a class of 20 students and the teacher is 20 years. When teachers leaves the class average of entire class decreases by 1.Calculate the age of teacher?

Such questions are very common in competitive examinations. All these questions are not at all difficult and can be easily solved using traditional average methods. But using  Average Concept carefully you can solve above questions without raising your pen and with lot of ease.

So Let us begin ,
In my previous article on averages,I had drawn one conclusion.

If a group of students have an average marks 43. We can also think it as every student havs got 43 marks
OR if a  If a group of students have an average marks X. We can also think it as every student has got X marks. got 4

Above statement is the soul for solving average questions quickly. So, Understand it well.
Let us solve Above questions :

Ques1: A average age of a class of 20 students is 20 years. When teachers' age is also included average of entire class  increases by 1.Calculate the age of teacher?
a) 39 Years.
b) 40 Years
c) 41 Years
d) 42 years

Solution:

Note : This solution may look lengthy initially but i promise if you go through it, you will learn the trick easily.

Step 1:  First, Convert this question into rupee problem to make things easy for you.

Here it is given average age of 20 students = 20 years.

Using the statement in red background you can say,

Age of  Every student in the class is 20 years.

( Let us convert it into rupee problem )

You can say Every student in the class is having 20 Rs.

( here we have converted age in to rupees to make it easier )

Now when teacher is included average increases by 1 ==> Average becomes 21.

If Average is 21 ===> Every one in the class including the teacher must have 21 Rs.

Now , Let us understand how average will become 21. I will explain you by showing you conversation between the teacher and a student named Pappu.

Scene1: Every Student in the Class is having 20 Rs.   ( initial average 20 )

Scene 2:    When teacher enters the Class.   ( average becomes 21 )

Teacher: " Now average of entire class is 21 Rs."

Pappu   : " But this means everyone must have 21 Rs. But we have only 20 Rs                                     each"

Teacher: " Yes, I will give you one rupee each so that everyone of you has 21 Rs."
( now teacher gives every student 1 rupee )

Pappu : " Sir,ok i agree now each of student is having 21 Rs. but 21 is  the average including you so you must have 21 Rs. too"

Teacher : " I have my 21 Rs."

Conclusion: Now everyone has 21 Rs. so average of the entire class will be 21.

Now let us Calculate how much money teacher had when he entered the class.

1) He gave 1 rupee each to 20 students = 20 Rs.

2) After giving 20 Rs. he is left with 21 Rs.

So total money with teacher when he entered the class = 20+21 =41 Rs.

Age of the teacher = 41 Years.

Hence option [c] is correct.

Ques2: Average age of a class of 20 students and the teacher is 20 years. When teacher leaves the class average of class decreases by 1.Calculate the age of teacher?

a) 39 Years.
b) 40 Years
c) 41 Years
d) 42 years

First, Convert this question into rupee problem to make things easy for you.

Here it is given average age of 20 students + Teacher  = 20 years.

Using the statement in red background you can say,

Age of  Everyone in the class including the teacher is 20 years.

( Let us convert it into rupee problem )

You can say Everyone including the teacher in the class is having 20 Rs.

( here we have converted age in to rupees to make it easier )

Now when teacher leaves =>Averaged  decreases by 1 ==> Average becomes 19..

If Average is 19 ===> Every one in the class after teacher left must have 19 Rs.

Now , Let us understand how average will become 19. I will explain you by showing you conversation between the teacher and a student named Pappu.

Scene1: Every Student in the Class is having 20 Rs. (initial average 20 )

Scene 2:    When teacher leaves the class.    ( average becomes 19 )

Teacher: " When i will leave average of your class will be 19."

Pappu   : " But this means everyone must have 19 Rs. But we have 20 Rs                                 each"

Teacher: " Yes, Do one thing , all of you give me 1 rupee each  so that everyone of you has 19 Rs."
( now each student gives 1 rupee to teacher: In total teacher gets 20 Rs. )  ----- (1)

Pappu : " Sir,ok i agree now each of student is having 19 Rs. but you too had 20 Rs since average including you was 20."

Teacher : " I have my 20 Rs."            ----------------------- (2)
Now teacher goes out.

Conclusion: Now everyone left in the class has 19 Rs. so average of the class will be 19

Now let us Calculate how much money teacher takes with him when he left the class.

1) He got 1 rupee each from 20 students = 20 Rs.

2) He already had his 20 Rs.

So total money with teacher when he left the class = 20+20 =40 Rs.

Age of the teacher = 40 Years.

Hence option [b] is correct.

Try few by Yourself:

MOCK QUESTIONS

Q1] Average runs per inning by Virat Kohli in a tournament is 44 after 14 innings. How much runs he should make in 15th inning so that average increase by 2.

a) 70
b) 72
c) 74
d) 76

Q2] Average runs per inning by Virat Kohli in a tournament is 44 after 9 innings. How much runs he should make in 10th inning so that average increase by 1.

a) 53
b) 54
c) 55
d) 56

Q3]: average age of a class of 30 students is 20 years. When teachers' age is also included average of entire class  increases by 1.Calculate the age of teacher?
a) 49
b) 50
c) 51
d) 52

Q4]: average age of a class of 30 students and the teacher is 20 years. When teachers leaves the class average of entire class decreases by 1.Calculate the age of teacher?

a) 48
b) 49
c) 50
d) 51
Enroll for Online Courses By RaMo (99.99%iler CAT)  and give A boost to your preparation. 