Q28 of 47 Page 1

two pipes running together can fill a tank in minutes. If one pipes takes 5 minutes more than, the other to fill the tank separately, find the time in which each pipe would fill the tank separately.

Time taken by both pipes to fill the tank


Work done by both pipes in a minute = 9/100


Let the time taken by one pipe to fill tank = x minutes


Work done by first pipe in one minute = 1/x


Time taken by another pipe to fill tank = x + 5 minutes


Work done by second pipe in one minute = 1/x + 5


work done by both pipes in one minute =


So,




200x + 500 = 9x2 + 45x


9x2 - 155x - 500 = 0


9x2 - 180x + 25x - 500 = 0


9x(x - 20) + 25(x - 20) = 0


(9x + 25)(x - 20) = 0


x = 20 or x = - 25/9(not possible as time is not negative)


time taken by first tank = 20 minutes and second tank is 25 minutes.


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