SOLUTION: jeff takes 5 hours longer to build a fence than it takes bill. When they work togehter , it takes them 6 hours . How long would it take bill alone to do the job alone?
Algebra ->
Customizable Word Problem Solvers
-> Misc
-> SOLUTION: jeff takes 5 hours longer to build a fence than it takes bill. When they work togehter , it takes them 6 hours . How long would it take bill alone to do the job alone?
Log On
Question 605077: jeff takes 5 hours longer to build a fence than it takes bill. When they work togehter , it takes them 6 hours . How long would it take bill alone to do the job alone? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! jeff takes 5 hours longer to build a fence than it takes bill.
When they work together, it takes them 6 hours .
How long would it take bill alone to do the job alone?
:
Let b = time required by Bill to build the fence
then
(b+5) = time required by Jeff
:
Let the completed job = 1
: + = 1
multiply by b(b+5)
6(b+5) + 6b = b(b+5)
6b + 30 + 6b = b^2 + 5b
0 = b^2 + 5b - 12b - 30
a quadratic equation
b^2 - 7b - 30 = 0
(b-10)(b+3) = 0
The positive solution
b = 10 hrs for Bill to do the job
and
10 + 5 = 15 hrs for Jeff
