Pipe & Work Question Answers

Quant/Math - CAT 2008

CAT Sample Questions - Question 4 the day : June 15, 2004

The question for the day is from the topic Work and Time..

Ram, who is half as efficient as Krish, will take 24 days to complete a work if he worked alone. If Ram and Krish worked together, how long will they take to complete the work?

(1)	16 days		(2)	12 days
(3)	8 days		(4)	18 days

 

Correct choice - (3) Correct Answer -(8 days)

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Explanatory Answer

Ram takes 24 days to complete the work, if he works alone.
As Krish is twice as efficient as Ram is, Krish will take half the time to complete the work when Krish works alone, i.e., in 12 days.

Ram completes  1/24 th of the work in a day.
Krish completes 1/12 th of the work in a day.
When they work together, they will complete  1/24  +  1/12  =  1+2 / 24  = 1/8 th work in a day.
Therefore, when they work together they will complete the work in 8 days.