Three pipes attached to a tank

Three pipes, a, b, & C are attached to a tank. A & b can fill it in 20 & 30 minutes respectively while C can empty it in 15 minutes. If a, b & C are kept open successively for 1 minute each, how soon will the tank be filled?

Answered by: chris on: May 25th, 2012

you can not fill the tank while pipe c is still opened.. a & b is for storage and pipe C is for draining..

Answered by: saritha1406 on: Oct 13th, 2010

The part of tank filled by Pipe A in 1 min = 1/20
The part of tank filled by Pipe B in 1 min = 1/30
The part of tank emptied by Pipe C in 1 min = 1/15
The part of tank filled in 1 min is 1/20 + 1/30 - 1/15 = 1/60

The total time taken to fill the tank is 60 min = 1 hr.

A family planning weekend trip

A family, planning a weekend trip, decides to spend not more than a total of 8 hours driving. By leaving early in the morning, they can average 40 miles per hour on the way to their destination. Due to the heavy Sunday traffic, they can average only 30 miles per hour on the return trip. What is the farthest...

Answered by: atul on: Aug 7th, 2011

137.5mile

Answered by: saritha1406 on: Oct 13th, 2010

Here 1 km = 0.625 miles (approximately)40 miles = 40 * 1/0.625 kms/hr = 64 kms/hr30 miles = 30 * 1/0.625 kms/hr = 48 kms/hrh= time taken to travel destinationDistance travelled till destination = 64 *...