SOLUTION: Two pipes running together can fill a tank in 15 minutes. The larger pipe can fill the tank 16 minutes sooner than the smaller pipe. Find the time in which each pipe alone can fill

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Two pipes running together can fill a tank in 15 minutes. The larger pipe can fill the tank 16 minutes sooner than the smaller pipe. Find the time in which each pipe alone can fill      Log On


   



Question 979707: Two pipes running together can fill a tank in 15 minutes. The larger pipe can fill the tank 16 minutes sooner than the smaller pipe. Find the time in which each pipe alone can fill the tank.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Two pipes running together can fill a tank in 15 minutes.
The larger pipe can fill the tank 16 minutes sooner than the smaller pipe. Find the time in which each pipe alone can fill the tank.
:
Let x = the time required by the larger pipe
then
(x+16) = time required by the smaller
:
let the completed job = 1 (a full tank)
:
A shared work equation
15%2Fx + 15%2F%28%28x%2B16%29%29 = 1
multiply equation by x(x+16), cancel the denominators and you have
15(x+16) + 15x = x(x+16)
15x + 240 + 15x = x^2 + 16x
Arrange as a quadratic equation on the right
0 = x^2 + 16x - 30x - 240
x^2 - 14x - 240 = 0
Factors to
(x-24)(x+10) = 0
positive solution
x = 24 minutes the time of the larger pipe
then
24 + 16 = 40 min for smaller pipe
:
;
See if that checks out
15%2F24 + 15%2F40 =
.625 + .375 = 1
: