SOLUTION: Fran can write a computer program in 9 days. If Doug helps her, they can write the program in 6 days. How long would it take Doug to write the program by himself?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Fran can write a computer program in 9 days. If Doug helps her, they can write the program in 6 days. How long would it take Doug to write the program by himself?      Log On


   



Question 610665: Fran can write a computer program in 9 days. If Doug helps her, they can write the
program in 6 days. How long would it take Doug to write the program by himself?

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Fran can write a computer program in 9 days. If Doug helps her, they can write the
program in 6 days. How long would it take Doug to write the program by himself?
.
Let x = time (days) it takes for Doug alone
then
6(1/9 + 1/x) = 1
multiplying both sides by 9x:
6(x + 9) = 9x
6x + 54 = 9x
54 = 3x
18 days = x