A can do `(1)/(10)` th of a piece of work in a day. B can do the same work in 15 days. In how many days can they do the same work, working together?

Options

A. 5
B. 6
C. 8
D. 9

Answer

B

Explanation

A's 1 day work `=(1)/(10)`
As B can do the work in 15 days, B's 1 day work = `(1)/(15).`
(A + B)'s 1 day work =`(1)/(10) + (1)/(15)`
`= (3 + 2)/(30) = (5)/(30) = (1)/(6)`
A and B together can finish the entire work in 6 days.
Hence, the correct option is (b).