A tank is filled by 3 pipes with uniform flow. The first two pipes operating simultaneously fill the tan in the same time during which the tank is filled by the third pipe alone. The 2nd pipe fills the tank 5 hours faster than first pipe and 4 hours slower than third pipe. The time required by first pipe is
Select the correct option
A) 13 hours	B) 45 hours	C) 15 hours	D) 12 hours	E) 11 hours
If first pipe fills tank in x hrs, then second pipe fills tank in x-5 hrs and 3rd pipe fills tank in x-9 hrs, then   as per given condition   1/x +1/(x-5) = 1/(x-9)   solving it, we get x= 15 hrs   ANSWER:15 hours
<result>C</result>
A tank is filled by 3 pipes with uniform flow. The first two pipes operating simultaneously fill the tan in the same time during which the tank is filled by the third pipe alone. The 2nd pipe fills the tank 5 hours faster than first pipe and 4 hours slower than third pipe. The time required by first pipe is