SOLUTION: Please, I need help setting this prob up...this is college pre-algebr extra credit. Painter A paints a house in 3 days Painter B paints a house in 5 days How long would it t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Please, I need help setting this prob up...this is college pre-algebr extra credit. Painter A paints a house in 3 days Painter B paints a house in 5 days How long would it t      Log On


   



Question 517460: Please, I need help setting this prob up...this is college pre-algebr extra credit.
Painter A paints a house in 3 days
Painter B paints a house in 5 days
How long would it take if they painted together?
So I know it takes B 2 more days than A so is it something like B+2=?? or 1/3+1/5=X

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
close
We know it has to be less than 3 days since painter a can do it alone in three days.
x/3+x/5=1
Why 1?
One is the whole job.
In one day painter a does 1/3 of the job and painter b does 1/5 of the job.
In x days painter a does x/3 and painter b does x/5 of the job.
5x+3x=15
8x=15
x=15/8
x=1 7/8 days
Assuming a work day is 8 hours, it will take 15 hours together.