SOLUTION: if one guy can empty a pool in 24 hours and another guy can empty a pool in 18 hours how long would it take both guys to empty the pool?

Question 285542: if one guy can empty a pool in 24 hours and another guy can empty a pool in 18 hours how long would it take both guys to empty the pool?
Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Let x=amount of time it takes both guys to empty the pool
Both guys empty at the rate of 1/x pool per hour
1st guy empties at the rate of 1/24 pool per hour
2nd guy empties at the rate of 1/18 pool per hour
So, both guys empty at the rate of 1/24 + 1/18 pool per hour.
1/24 + 1/18= 1/x multiply each term by 72x
3x+4x=74
7x=72
x=72/7 or 10 and 2/7 hours
CK
(72/7)*(1/24)+(72/7)(1/18) needs to equal 1 pool
3/7 + 4/7=7/7=1
Hope this helps--ptaylor

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