# Time and Work Questions

**FACTS AND FORMULAE FOR TIME AND WORK QUESTIONS**

**1. **If A can do a piece of work in n days, then A's 1 day's work =

**2. **If A’s 1 day's work =, then A can finish the work in n days.

**3. **A is thrice as good a workman as B, then:

Ratio of work done by A and B = 3 : 1.

Ratio of times taken by A and B to finish a work = 1 : 3.

NOTE :

Hence,

Whole work is always considered as 1, in terms of fraction and 100% , in terms of percentage.

In general, number of day's or hours =

A) 18 days | B) 24 days |

C) 30 days | D) 36 days |

Explanation:

2(A+B+C)'s 1 day work =

=>(A+B+C)'s 1 day's work=

work done by A,B and C in 10 days=

Remaining work=

A's 1 day's work =

Now, work is done by A in 1 day.

So, work wil be done by A in = 18 days

A) 20days | B) 40 days |

C) 50 days | D) 60 days |

Explanation:

(A+B)'s 1 day's work=1/20

C's 1 day work=1/60

(A+B+C)'s 1 day's work=

Also A's 1 day's work =(B+C)'s 1 day's work

we get: 2 * (A's 1 day 's work)=1/15

=>A's 1 day's work=1/30

B's 1 day's work=

So, B alone could do the work in 60 days.

A) 4 days | B) 6 days |

C) 8 days | D) 10 days |

Explanation:

Ratio of rates of working of A and B =2:1. So, ratio of times taken =1:2

A's 1 day's work=1/9

B's 1 day's work=1/18

(A+B)'s 1 day's work=

so, A and B together can finish the work in 6 days

A) 10 % | B) 14 2/7 % |

C) 20 % | D) Can't be determined |

Explanation:

Let he initially employed x workers which works for D days and he estimated 100 days for the whole work and then he doubled the worker for (100-D) days.

D * x +(100- D) * 2x= 175x

=> D= 25 days

Now , the work done in 25 days = 25x

Total work = 175x

therefore, workdone before increasing the no of workers = %