A pipe fills a tank in 6 hours another empties it in 8 hours. Both open: how long to fill?
A
24 hours
B
20 hours
C
18 hours
D
16 hours
Correct Answer: Option A — 24 hours
Explanation:
Net fill rate = 1/6 - 1/8 = 4/24 - 3/24 = 1/24 per hour. Time = 24 hours. Pipes and cisterns problems use the same framework as work problem...
Net fill rate = 1/6 - 1/8 = 4/24 - 3/24 = 1/24 per hour. Time = 24 hours. Pipes and cisterns problems use the same framework as work problems where filling pipes add rates and draining pipes subtract rates. Combining rates correctly is the key skill tested in these extremely common aptitude questions.