If 20 teachers out of a faculty of 80 are transferred, what percentage of the original faculty remains ?

A. 30 days
B. 25 days
C. 24 days
D. 20 days
Part of work done by 1 man in a day = 1/m Part of work done by 1 woman in a day
= 1/w (2/m)+(12/w) = (1/4) (4/m)+(6/w) = (1/5) Solving,
1/m = 1/40 ,1/w = 1/60 (1/m)+(1/w) = 5/120 = 1/24

A. 10
B. 9
C. 11
D. 12
Work done by P in 1 day = 1/24
Work done by Q in 1 day = 1/9
Work done by R in 1 day = 1/12
Work done by Q and R in 1 day = 1/9 + 1/12 = 7/36
Work done by Q and R in 3 days = 3×7/36 = 7/12
Remaining work = 1 – 7/12 = 5/12
Number of days in which P can finish the remaining work = (5/12) / (1/24) = 10