SOLUTION: There are 2 overflow pipes at a dam. The larger overflow pipe can lower the level of the water in the reservoir by 1 foot in 45 minutes. The smaller one lowers the level of water

Question 40454This question is from textbook
: There are 2 overflow pipes at a dam. The larger overflow pipe can lower the level of the water in the reservoir by 1 foot in 45 minutes. The smaller one lowers the level of water by 1 foot in 2 hours 15 minutes. If both overflow pipes are open at the same time, how long will it take them to lower the level of water by 1 foot? Thenk you in advance. This question is from textbook

Found 2 solutions by josmiceli, Nate:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
rate1 + rate2 = combined rate
(1 ft / 135 min) + (1 ft / 45 min) = 1 ft / x min)
LCD is 135
1/135 + 3/135 = 1/x
4/135 = 1/x
4x = 135
x = 33.75
33 min 45 sec with both pipes open
Answer by Nate(3500) (Show Source): You can put this solution on YOUR website!
Rate of the first pipe is (1/45). The rate of the second pipe is (1/135).
Rate times time yields work, so the you have: (t/45) and (t/135).
one job is being done

(0.75)(60) = 45
33 minutes and 45 seconds
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