SOLUTION: A sink has two faucets: one for hot water and one for cold water. The sink can be filled by a cold water faucet in 3.9 minutes. If both faucets are open, the sink is filled in 3 mi

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: A sink has two faucets: one for hot water and one for cold water. The sink can be filled by a cold water faucet in 3.9 minutes. If both faucets are open, the sink is filled in 3 mi      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 968661: A sink has two faucets: one for hot water and one for cold water. The sink can be filled by a cold water faucet in 3.9 minutes. If both faucets are open, the sink is filled in 3 minutes. How long does it take to fill the sink with just the hot water faucet open?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of filling to get rate
of filling together
Let +t+ = time in minutes for
the hot water faucet to fill sink
-----------------------------
Rate for hot water faucet:
[ 1 sink filled ] / [ t min ]
Rate for cold water faucet:
[ 1 sink filled ] / [ 3.9 min ]
--------------------------
+1%2Ft+%2B+1%2F3.9+=+1%2F3+
Multiply both sides by +3%2A3.9%2At+
+3%2A3.9+%2B+3t+=+3.9t+
+11.7++=+.9t+
+t+=+13+
It takes 13 minutes for
the hot water faucet to fill sink