SOLUTION: Pipe A can fill a tank in 4 hours, and pipe B can fill the tank in 3 hours. With the tank empty, pipe A is turned on. One hour later, pipe B is turned on. How long will pipe B run

Question 435961: Pipe A can fill a tank in 4 hours, and pipe B can fill the tank in 3 hours. With the tank empty, pipe A is turned on. One hour later, pipe B is turned on. How long will pipe B run before the tank is filled?
Please help me with this questions, thanks.
Answer by jorel1380(3719) (Show Source): You can put this solution on YOUR website!
If pipe A can fill a tank in 4 hours, and it is left on for an hour, it will have filled 1/4 of the tank. Together , the pipes can fill 1/4+1/3 tank an hour.
----------------
(1/4)t+(1/3)t=3/4
Multiply both sides by 12
3t+4t=9
7t=9
t=9/7 hours
Pipe B will run along with pipe A together for 9/7 hours before they fill the tank.
RELATED QUESTIONS
A pipe can fill a tank in 3 hours. Another pipe can empty the tank in 6 hours. If the... (answered by josmiceli)

An inlet pipe can fill a tank in 3 hours. An outlet pipe can empty the tank in 6 hours. (answered by Alan3354)

Pipe A can fill a tank in 4 hours, and pipe B can fill the tnk in half hte time required... (answered by venugopalramana)

Pipe A can fill a tank alone in 5 hours and Pipe B can fill the tank alone in 4 hours. A (answered by ikleyn)

A pipe can fill a water tank in 24 hours. The drain can drain the tank in 18 hours. If... (answered by richwmiller)

The intake pipe can fill a tank in 4 hours when the outlet pipe is closed, but with the... (answered by scott8148)

Pipe A can fill a tank in 5 hours. Pipe B can fill the tank in 2 hours less time than it... (answered by stanbon,ankor@dixie-net.com)

One pipe can fill a tank in 6 hours and another pipe can fill the same tank in 3 hours. A (answered by macston)

Pipe A can fill a tank in 14 hours. Pipe B can empty a tank in 10 hours. Miscommunication (answered by stanbon)