# 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) 12 days | B) 18 days |

C) 24 days | D) 30 days |

Explanation:

A + B = C + D

| | | |

Ratio of efficiency 10x + 5x 9x + 6x

|________| |_________|

15x 15x

Therefore , ratio of efficiency of A:C =10:9

Therefore, ratio of days taken by A:C = 9:10

Therefore, number of days taken by A = 18 days

A) 3 hours | B) 4 hours |

C) 5 hours | D) None of these |

Explanation:

Rate of leakage = 8.33% per hour

Net efficiency = 50 - (16.66 + 8.33)= 25%

Time required = 100/25 = 4 hours

As the pipes are operating alternatively, thus their 2 minutes job is =

In the next 2 minutes the pipes can fill another part of cistern.

In 4 minutes the two pipes which are operating alternatively will fill

Remaining part =

Pipe A can fill of the cistern in 1 minute

Pipe A can fill of the cistern in = min

Total time taken to fill the Cistern

minutes

A) 1 day | B) 2 days |

C) 5 days | D) None of these |

Explanation:

Total work = 100+50 = 150man-days

In 8 days 100 man-days work has been completed. Now on 9th and 10th day there will be 25 workers. So in 2 days they wll complete additional 50 man- days work. Thus the work requires 2 more days.

A) 6 | B) 8 |

C) 9 | D) 12 |

Explanation:

Amit did the work in 56 days =

Rest work was done by Amit and Bharath = = 8 days

( since Amit and Bharath do the work in one day = )