Question 355083
let Pat alone do the job in x minutes
Mike takes x+15 minutes alone.
...
Pat does 1/x of the job in 1 minute
mike does 1/(x+15) of the job in 1 minute
together they will do 1/x+1/(x+15) of the job in 1 minute
= (x+15+x)/(x(x+15))
=2x+15/x(x+15)
they will take x(x+15)/2x+15 minutes = 15
x(x+15)/2x+15 = 15

x^2+15x=15(2x+15)
x^2+15x=30x+225
x^2-15x-225=0
Pat does the job alone in 24.27 minutes
Mike will take 39.27 minutes alone
m.ananth@hotmail.ca