SOLUTION: an oil tank is being filled by two pipes. On pipe working alone could fill the pipe in 18 hours. The second pipe working alone could fill the tank in 15 hours. How long will it t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: an oil tank is being filled by two pipes. On pipe working alone could fill the pipe in 18 hours. The second pipe working alone could fill the tank in 15 hours. How long will it t      Log On


   



Question 354111: an oil tank is being filled by two pipes. On pipe working alone could fill the pipe in 18 hours. The second pipe working alone could fill the tank in 15 hours. How long will it take to fill the tank using the two pipes at the same time?
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
1st pipe fills 1/18 of the tank in 1 hr; 2nd pipe fills 1/15 of the tank in 1 hr.
1/18 + 1/15
=5/90 + 6/90
=11/90 of tank filled in 1 hr.
90/11 hrs it takes to fill the tank.
.
Ed