SOLUTION: A pool can be filled by one pipe in 20 hours and by a second pipe 60 hours. How long will it take using both pipes to fill the pool? explain Please

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A pool can be filled by one pipe in 20 hours and by a second pipe 60 hours. How long will it take using both pipes to fill the pool? explain Please      Log On


   

Question 854115: A pool can be filled by one pipe in 20 hours and by a second pipe 60 hours. How long will it take using both pipes to fill the pool? explain Please
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The rate of filling of the 1st pipe is:
( 1 pool filled ) / ( 20 hrs )
The rate of filling of the 2nd pipe is:
( 1 pool filled ) / ( 60 hrs )
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Let +t+ = the time in hours for the pipes
to fill the pool together. the rate of both filling is:
( 1 pool filled ) / ( t hrs )
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To get the rate of filling of both pipes
together, add their rates of filling:
+1%2F20+%2B+1%2F60+=+1%2Ft+
Multiply both sides by +60t+
+3t+%2B+t+=+60+
+4t+=+60+
+t+=+15+
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With both pipes filling together, the
pool is filled in 15 hrs