Question

X, Y and Z together can do a piece of work in 8 days while X and Z together can do it in 12 days. Y alone will do the same work in a) 16 days b) 20 days c) 24 days d) 28 days

Answer 1

As 1/x+1/y+1/z = 1/10. —(1)

1/y = (1/2)*(1/x +1/z). — (2)

So, 2/y = 1/x + 1/z

From equation 1,

1/y + 2/y = 1/10

y = 30.

Thus y takes 30 days to complete whole work.

Therefore y takes 15 days to complete half of the work.