42.A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With the help of C, they did the job in 4 days only. Then, C alone can do the job in
A. 9x1/5 days B. 9x2/5 days
C. 9x3/5 days D. 10 days
Answer:
(A+B+C)'s 1 day's work = 1/4
A's 1 day's work = 1/16
B's 1 day's work = 1/12
C's 1 day's work = 1/4-(1/16+1/12)
= (1/4 - 7/48)
= 5/48.
So,C alone can do the work in 48/5 =9x3/5 days.
