SOLUTION: Pump A can fill up an empty pool in 6 hours. Pump B can fill up the same empty pool in 12 hours. If the pool is already 1/3 full, how long will it take for both of the pumps workin

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Pump A can fill up an empty pool in 6 hours. Pump B can fill up the same empty pool in 12 hours. If the pool is already 1/3 full, how long will it take for both of the pumps workin      Log On


   

Question 497611: Pump A can fill up an empty pool in 6 hours. Pump B can fill up the same empty pool in 12 hours. If the pool is already 1/3 full, how long will it take for both of the pumps working together to fill up the remainder of the pool?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Pump A can fill up an empty pool in 6 hours.
Pump B can fill up the same empty pool in 12 hours.
If the pool is already 1/3 full, how long will it take for both of the pumps
working together to fill up the remainder of the pool?
:
Let t = time to complete filling the pool by both Pumps
Let a full pool = 1, then the amt remaining to be filled = 2%2F3
:
t%2F6 + t%2F12 = 2%2F3
multiply equation by 12
12*t%2F6 + 12*t%2F12 = 12*2%2F3
cancel the denominators and you have
2t + t = 4(2)
3t = 8
t = 8%2F3
t = 22%2F3 hrs to complete filling the pool by both pumps