(A) 20
(B) 34
(C) 40
(D) 56
Correct Option is: C
Z alone can finish the work in 120 days.
As given Z does half as much work as X and Y together
=> (X + Y) can do it in 60 days
(X+ Y)s 1 days wok = 1/60.
X’s 1 days work : Y’s 1 days Work = 1/2 : 1 = 1:2(given)
X’s 1 day’s work = (1/60) x (1/3) = (1/180)
X’s 1 days work = (1/60) x (2/3) = 1/90
(X+Y+Z)’s 1 day’s work = (1/180) + (1/90) + (1/120)
=(2+4+3)/360
=9/360
= 1/40
All the three together will finish it in 40 days