Correct Answer: Option A
Work done by X in 8 days =(1/40 x 8) = 1/5.
Remaining work = (1 – 1/5) = 4/5.
Now, 4/5 work is done by Y in 16 days.
Whole work will be done by Y in (16 x 5/4) = 20 days.
Therefore, X's 1 day's work = 1/40,
Y's 1 day's work = 1/20.
So, (X + Y)'s 1 day's work = (1/40 + 1/20) = 3/40.
Hence, X and Y will together complete the work in (40/3)
= 13(1/3) days.
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