Question
Sat October 27, 2012 By: Arnav Sharma

Q1

Expert Reply
Mon October 29, 2012
Time taken by first pipe to fill the tank = (x + 2) hours
Time taken by second pipe to fill the tank = (x + 7) hours
 
Time taken to fill the tank by both pipes together = (x+2) (x + 7) / x + 2 + x + 7 = (x+2) (x + 7) / 2x + 9
 
Therefore, (x+2) (x + 7) / 2x + 9 = 6
x2 + 9x + 14 = 12x + 54
x2 - 3x - 40 = 0
(x + 5) (x - 8) = 0
x = -5 or 8
But, x cannot be negative. Therefore, x = 8
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