P can do a work in the same time in which Q and R together can do it. If P and Q work together, the work can be completed in 10 days. R alone needs 50 days to complete the same work. then Q alone can do it in ?
A.
15 days
B.
20 days
C.
25 days
D.
30 days
Answer: Option C
Explanation:
Work done by P and Q in 1 day = 1/10 Work done by R in 1 day = 1/50 Work done by P, Q and R in 1 day = 1/10 + 1/50 = 6/50 But Work done by P in 1 day = Work done by Q and R in 1 day . Hence the above equation can be written as Work done by P in 1 day × 2 = 6/50 => Work done by P in 1 day = 3/50 => Work done by Q and R in 1 day = 3/50 Hence work done by Q in 1 day = 3/50 – 1/50 = 2/50 = 1/25 So Q alone can do the work in 25 days
A leak in the bottom of a tank can empty the full tank in 6 hrs. An inlet pipe fills water at the rate of 4 lit. a minute. When the tank is full, the inlet is opened and due to the leak, the tank is empty in 8 hrs. The capacity of the tank in liters is ?
A tap can fill a tank in 32 min. and another can empty it in 16 min. If the tank is already half full and both the tanks are opened together, the tank will be ?
A.
12 min
B.
14 min
C.
16 min
D.
18 min
Answer: Option C
Explanation:
In this problem, rate of water pipe (waste) is more, the tank will be emptied when the pipes are opened. Work done in total emptying in 1 min. =1/16−1/32=1/32 Now, full tank will be emptied by them in 32 minutes. Half full tank will be emptied in 16 minutes.
Twelve men can do a work in twenty days while twenty women can finish the same work in sixteen days. Find the ratio between the capacity of a man and a woman.?
A.
3:4
B.
5:4
C.
4:3
D.
5:3
Answer: Option C
Explanation:
Part of work completed by a man in a day = 1/(12*20) = 1/240 Part of work completed by a woman in a day = 1/(20*16) = 1/320 Ratio of their capacities = (1/240):(1/320) = 320:240 = 4:3
