SOLUTION: two pumps were required to pump the water out of a submerged area after a hurricane. Pump A,the large of the two pumps can pump the water out in 36 hours,whereas it would take pump

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Question 615958: two pumps were required to pump the water out of a submerged area after a hurricane. Pump A,the large of the two pumps can pump the water out in 36 hours,whereas it would take pump B 180 hours. both pumps were working for the first 9 hours until pump A broke. how long did it take pump B to pump out the remaining water?
Found 2 solutions by scott8148, ankor@dixie-net.com:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
in the 9 hrs that it runs, A pumps out 1/4 (9/36) of the water

it takes B 135 hr (3/4 * 180) to pump the remaining 3/4; but B has been pumping for 9 hrs, so only 126 hrs to finish

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
two pumps were required to pump the water out of a submerged area after a hurricane.
Pump A, the large of the two pumps can pump the water out in 36 hours, whereas it would take pump B 180 hours.
Both pumps were working for the first 9 hours until pump A broke.
How long did it take pump B to pump out the remaining water?
;
Let t = time to pump out the remain water
:
Let the completed job = 1, (all water pumped out)
:
9%2F36 + %28%28t%2B9%29%29%2F180 = 1
Reduce the fraction
1%2F4 + %28%28t%2B9%29%29%2F180 = 1
:
%28%28t%2B9%29%29%2F180 = 1 - 1%2F4
%28%28t%2B9%29%29%2F180 = 3%2F4
cross multiply
4(t+9) = 3 * 180
4t + 36 = 540
4t = 540 - 36
4t = 504
t = 504/4
t = 126 hrs to complete the job