(A) 30 5/9
(B) 29 4/9
(C) 31 3/5
(D) 29 5/9
Correct Option is: A
Time taken by M to finish the work = 45 days.
M’s 1 day’s work = 1/45
Time taken by N to finish the work = 40 days.
N’s 1 day’s work = 1/40
(M + N)’s 1 day’s work = (1/40+1/45) = (9+8)/360=17/360
(M + N)’s 5 day’s work (5 × 17/360) = 85/360=17/72
Remaining work (1 – 17/72) = 55/72
Now, 55/72 work is done by N in 1 day
Therefore, 55/72 work will be done by N in (55/72*40) days = 30 and 5/9 days.
Hence, the remaining work is done by B in 30 and 5/9 days.