48. A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is
A. 1/4 B. 1/10
C. 7/15 D. 8/15
Answer:
A's 1 day's work = 1/15
B's 1 day's work = 1/20
(A+B)'s 1 day's work = (1/15 + 1/20)
= 7/60.
(A+B)'s 4 day's work = (7/60x4)
= 7/15.
Remaining Work = (1-7/15)
