Q) X can do a piece of work in 40 days. He works at it for 8 days and then Y finished it in 16 days. How long will they together take to complete the work?

a) 13 1/3 days              b) 15 days             c) 20 days                d) 26 days

Ans:

X’s 1 day’s work = 1/40 ……….. (i)

∴ X’s 8 days’ work = 8 x 1/40 = 1/5

∴ Balance work = 1 – 1/5 = 4/5

Y completed 4/5 work in 16 days

Y will complete full work in = 16 /(4/5) = 20 days

Y’s 1 day’s work = 1/20 ………..(ii)

(X + Y)’s 1 day’s work = 1/40 + 1/20 = 3/40

Since Time taken by (A + B) to finish 3/40 work = 1 day

∴ Time taken by (A + B) to finish whole work = 1 /(3/40) = 40/3 = 13 1/3 days

Hence, Answer is [A].

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