Pipe & Work Question Answers

Time and Work - Quant/Math - CAT 2008

Question 4 the day: June 13, 2003

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

X alone can do a piece of work in 15 days and Y alone can do it in 10 days. X and Y undertook to do it for Rs. 720. With the help of Z they finished it in 5 days. How much is paid to Z?

(1)	Rs. 360			(2)	Rs. 120
(3)	Rs. 240			(4)	Rs. 300

Correct Answer - (2)

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Solution:


In one day X can finish 1/15^th of the work.

In one day Y can finish 1/10^th of the work.

Let us say that in one day Z can finish 1/Z^th of the work.

When all the three work together in one day they can finish 1/15 + 1/10 + 1/Z = 1/5^th of the work.

Therefore, 1/Z = 1/30.

Ratio of their efficiencies = 1/15: 1/10: 1/30 = 2: 3: 1.Therefore Z receives 1/6^th of the total money.

According to their efficiencies money is divided as 240: 360: 120.

Hence, the share of Z = Rs. 120.