Four two-way pipes A, B, C and D can either fill an empty tank or drain the full tank in 4, 10, 12 and 20 minutes respectively. All four pipes were opened simultaneously when the tank is empty. Under which of the following conditions the tank would be half filled after 30 minutes?
Explanation:
Let the capacity of the tank = LCM(4, 10, 12, 20) = 60 units ∴ Efficiency of A, B, C and D = 15, 6, 5, 3 units/minute respectively.
We need to check options now, Option 1: Work Done in a minute = 15 – 6 – 5 – 3 = 1 unit ∴ After 30 minutes, the tank will be half filled.
We don’t have to check other options. Hence, option (a).
» Your doubt will be displayed only after approval.
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.