23. Two persons A and B working together can dig a trench in 8 hours while A alone can dig it in 12 hours. In how many hours B alone can dig such a trench?
A.14 Hours B.24 Hours
C.8 Hours D.12 Hours
Answer:
(A + B)'s 1 hour's work = 1/8, A's 1 hour's work = 1/12
:. B's 1 hour's work=(1/8-1/12 )=1/24
Hence B alone can dig the trench in 24 hours.
