Question:
A cistern has a leak which would empty it in 8 hours.A tap is turned on which admits 6 litres a minute in the cistern, and it is now emptied in 12 hours. How many litres does the cistern hold?
A8460 L
B4320 L
C8640 L
D4230 L
Answer:
C. 8640 L
Explanation:
Work done by leak in 1 hour = 1/8 Total work done by both pipes in 1 hour = 1/12 Work done by the pipe in 1 h = (1 / 8 – 1 / 12) = 1 / 24 Work done by the pipe in 1 min = 1 / 24 × 1 / 60 = 1 / 1440 Volume of 1 / 1440 part = 6L Volume of the whole cistern = 6 × 1440 = 8640