It takes Jake 9 hours longer than Joe to rebuild an engine. Working together, they can do the job in 20 hours. How long would it take each, working alone, to rebuild an engine?

Question

anonymous · Answer

take it suzi

anonymous · Answer

9 = 3^2
20 = 2^2 * 5
3^2 * 2^2 * 5
180 hours?

anonymous · Answer

jake does it in x hours.  Therefore, his rate is 1/x
Joe does it in y hours.  Therefore, his rate is 1/y
20/y+20/x = 1
y+9 = x
20/y + 20/(y+9) = 1
40y+180= y^2 +9y
y^2 -31y +180 = 0
then use the quadratic formula :D