This is fourth chapter of IBPS Quantitative Aptitude Online Course. The first three chapter links are given below. For best results you should read all the chapters in order

Chapter 1 – Click to read chapter 1

Chapter 2 – Click to read chapter 2

Chapter 3 – Click to read chapter 3

In this chapter we will cover topics like Time and Work and Clocks and Races. These two topics are very important from exams point of view. Every year in IBPS and other similar exams we have questions from these two topics.

**Time and Work**

Formula 1

If a person can do a piece of work in x days, he can do 1/x of the work in 1 day.

Formula 2

If A does a piece of work in m days and B does same piece of work in n days then both can do the piece of work in

[mn / (m+n)] days

Formula 3

If A does a piece of work in m days more than the time taken by A and B combined. B does the piece of work in n days more than the time taken by A and B combined then together they will take square root of ab time to finish the piece of work.

Formula 4

If the number of person doing a piece of work in increased then time taken to do the work will decrease.If the number of person doing a piece of work in decreased then time taken to do the work will increase.

Formula 5

A does a piece of work in m days, B does the same piece of work in n days and C does the same piece of work in p days, then together they will take

[mnp / (mn + np + pm)] days.

Formula 6

If A does a piece of work on m days and A and B together do the piece of work on n days then B will do the piece of work in

[mn/(m-n)] days

Formula 7

If A does a piece of work in m days, B does the same piece of work in n days and ABC together do the piece of work in p days, then

C alone can do it in days [mnp / (mn – mp-np)]

A and C together can do it in days [np/ (n-p)]

B and C together can do it in days [mp/ (m-p)]

Formula 8

If two taps or pipes P and Q take â€˜mâ€™ and â€˜nâ€™ hours respectively to fill a cistern or tank, then the two pipes together fill

(1/m + 1/n) part of the tank in 1 hour and

the entire tank is filled in [(mn)/(m+n)] hours.

**Races**

Formula 1

If two people are running in circular track with speed a and b in same direction then they will first meet at time

L/ (a-b)

and time for first meeting at starting point is

LCM of L/a and L/b

Formula 2

If two people are running in circular track with speed a and b in opposite direction then they will first meet at time

L/ (a+b)

and time for first meeting at starting point is

LCM of L/a and L/b

Formula 3

If A scores 100 points and B scores 90 points in a game then it is said that A gives B 10 points.

**Clocks**

The minute hand moves at a speed of 6 degree per min and hour hand moves at a speed of 1/2 degree per min.

Hands of clock make 180 degree 11 times in every 12 hours. They make other angles 22 times in 12 hours.

This is end of chapter 4 we will now cover remaining topics in next chapters.