SOLUTION: Two companies working together can clear a parcel of land in 9 hours. Working alone it would take Company A 7 hours longer to clear the land than it would Company B. How long would

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Two companies working together can clear a parcel of land in 9 hours. Working alone it would take Company A 7 hours longer to clear the land than it would Company B. How long would      Log On


   

Question 739940: Two companies working together can clear a parcel of land in 9 hours. Working alone it would take Company A 7 hours longer to clear the land than it would Company B. How long would it take Company B to clear the parcel of land alone?
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Two companies working together can clear a parcel of land in 9 hours. Working alone it would take Company A 7 hours longer to clear the land than it would Company B. How long would it take Company B to clear the parcel of land alone?
***
x=amt of time company B can clear the land alone
1/x= Its work rate
x+7=amt of time company A can clear the land alone
1/(x+7)=Its work rate
9 hrs=amt of time they can clear the land working together
1/9=their work rate
..
sum of individual work rates=work rate working together
1%2Fx%2B1%2F%28x%2B7%29=1%2F9
LCD:9x(x+7)
9%28x%2B7%29%2B9x=x%28x%2B7%29
9x%2B63%2B9x=x%5E2%2B7x
x%5E2-11x-63=0
solve for x using quadratic formula
x≈-4.16 (reject, x>0)
or
x≈15.16
amt of time company B can clear the land alone≈15.16 hrs