# 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) 4:18 pm | B) 3:09 pm |

C) 12:15 pm | D) 11:09 am |

Explanation:

Efficiency of P= 5%

Efficiency of Q= 4%

Efficiency of R= 2.5%

Efficiency of S= 2%

%

Thus, at 10 am pipe P,Q and R filled 30.5% of the cistern.

Now, the time taken by P,Q,R and S together to fill the remaining capacity of the cistern

= = =5 Hours and 9 minutes(approx)

Therefore, total time =4 hrs + 5hrs 9 mins

= 9 hrs and 9 mins

It means cistern will be filled up at 3:09 pm

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) 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

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 = )