A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in___?
A can do a certain work-in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in__?
A and B can do a work in 8 days, 13, and C can do the same work in 12 days. A, B and C together can finish it in 6 days. A and C together will do it in___?
P takes twice as much time as Q or thrice as much time as R to finish a piece of work. They can finish the work in 2 days if work together. How much time will Q take to do the work alone?
A.
6
B.
7
C.
8
D.
9
Answer: Option A
Explanation:
Let P takes x days to complete the work Then Q takes x/2 days and R takes x/3 days to finish the work Amount of work P does in 1 day = 1/x Amount of work Q does in 1 day = 2/x Amount of work R does in 1 day = 3/x Amount of work P,Q and R do in 1 day = 1/x + 2/x + 3/x = 1/x (1 + 2 + 3) = 6/x 6/x = 2 => x = 12 => Q takes 12/2 days = 6 days to complete the work
