# 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) 2:6:3 | B) 2:3:6 |

C) 1:2:3 | D) 3:1:2 |

Explanation:

A : B : C

Ratio of efficiency 3 : 1 : 2

Ratio of No.of days : :

or 2 : 6 : 3

Hence A is correct.

A) 27 days | B) 12 days |

C) 25 days | D) 18 days |

Explanation:

x= 20 and x=-14

so, the acceptable values is x=20

Total work = = 18 x 20 =360 unit

Now 360 = 30 x k

k=12 days

A) 1/24 days | B) 7/24 days |

C) 24/7 days | D) 4 days |

Explanation:

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

so, A,B and C together will complete the work in 24/7 days.

A) 4.5 | B) 5 |

C) 6 | D) 9 1/3 |

Explanation:

A : B : C

Efficiency 10 : 9 : 6

No of days 9x : 10x : 15x

15x-9x = 6

x = 1

Number of days taken b A = 9

Number of days taken by B= 10

Number of days taken by C = 15

work done by B and C in initial 2 days = =

rest work =

Number of days required by A to finish work = = 6 days

A) 48 min | B) 54 min |

C) 30 min | D) none of these |

Explanation:

**In ideal Case:**

Time taken to fill the half tank by A and B = = hours

Time taken by A,B and C to fill rest half of the tank = = 3 hours

Total time = = 4 hours 12 min

**In second case:**

** **Time taken to fill tank by A and B = hours

Time taken by A,B and C to fill rest tank = hours

Total time = =3 hours 18 min

Therefore , difference in time = 54 minutes