SOLUTION: John can assemble a chair in 15 minutes more time than it takes Harold to assemble the same chair. If they work together, they can complete the job in 18 minutes. How long does it

Algebra ->  Expressions-with-variables -> SOLUTION: John can assemble a chair in 15 minutes more time than it takes Harold to assemble the same chair. If they work together, they can complete the job in 18 minutes. How long does it       Log On


   

Question 39431: John can assemble a chair in 15 minutes more time than it takes Harold to assemble the same chair. If they work together, they can complete the job in 18 minutes. How long does it take each man to assemble the chair alone?
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
JOhn can assemble the chair in x+15 minutes
Harold can assmble it in x minutes.
Equation:
1%2F%28x%2B15%29%2B1%2F%28x%29=1%2F18
1%28x%2B15%2Bx%29=%28%28x%29%28x%2B15%29%29%2F18
2x%2B15=%28x%5E2%2B15x%29%2F18
36x%2B270=x%5E2%2B15x
x%5E2-21x-270=0
x+=+%28-%28-21%29+%2B-+sqrt%28+%28-21%29%5E2-4%2A1%2A-270+%29%29%2F%282%2A1%29+
x=30
30+15=45
Hence, it takes John 45 minutes to assemble the chair, and it takes Harold 30 minutes to assemble the chair.
Paul.