Question 48

P, Q and R work together to finish a work. P and Q finish 70% of the work while Q and R finish 50% of the work. Who will finish first, if they work alone?

Solution

Total work = 100%

Work done by (P + Q) = 70%

Work done by (Q + R) = 50%

Work done by (P + Q) and (Q + R) = 70% + 50% = 120%

Work done by (P + Q + R) = 100%

now,

(P + Q) + (Q + R) - (P + Q + R) = 120 - 100 = 20%

Q = 20%

Work done by P = 70 - 20 = 50%

Work done by R = 50- 20 = 30%

P works 50% of the total work in same time so P will finish the work first.

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