SOLUTION: when the tub is on full, it can fill the tub to overflowing in 20 minutes (ignore overflow drain). the tub's drain can empty the tub in 15 minutes. My four-year-old has turned the

Algebra ->  Rate-of-work-word-problems -> SOLUTION: when the tub is on full, it can fill the tub to overflowing in 20 minutes (ignore overflow drain). the tub's drain can empty the tub in 15 minutes. My four-year-old has turned the       Log On


   



Question 585491: when the tub is on full, it can fill the tub to overflowing in 20 minutes (ignore overflow drain). the tub's drain can empty the tub in 15 minutes. My four-year-old has turned the faucet on full and the drain is closed. just as the tub starts to overflow, I run in to turn it off, but the handle breaks off, leaving the water running at full power. I yank the drain open.How long will it take the tube to empty, with the faucet still on, but the drain is now open?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
when the tub is on full, it can fill the tub to overflowing in 20 minutes (ignore overflow drain).
the tub's drain can empty the tub in 15 minutes.
My four-year-old has turned the faucet on full and the drain is closed.
just as the tub starts to overflow, I run in to turn it off, but the handle breaks off, leaving the water running at full power.
I yank the drain open.
How long will it take the tube to empty, with the faucet still on, but the drain is now open?
:
Let t = time required to empty the tub with both faucet and drain open
Let the completed job = 1 (An empty tub)
:
t%2F15 - t%2F20 = 1
multiply by 60 to clear the denominators
60*t%2F15 - 60*t%2F20 = 60
cancel the denominators
4t - 3t = 60
t = 60 minutes to empty the tub
:
:
Check this
60%2F15 - 60%2F20 = 1