Math Help - Rational Expressions (Problem Solving Q)

Hi, it's my first time posting here and I need urgent help. I am doing a problem solving question for my Intermediate Algebra class and I am stuck on one particular question.

The question reads:

A Homeowner estimates that it will take her 8 days to roof her house. A professional roofer estimates that he could roof the house in 5 days. How long will it take if the homeowner helps the roofer?

Can someone please help? Thanks in advance.

Homeowner: 1 roof / 8 days = (1/8) roof / day
Contractor: 1 roof / 5 days = (1/5) roof / day

Homeowner + Contractor = (1/8) roof / day + (1/5) roof /day
= (13/40) roof / day

1 roof / ((13/40) roof/day) = 40/13 days = about 3.1

Originally Posted by Mentia

Homeowner: 1 roof / 8 days = (1/8) roof / day
Contractor: 1 roof / 5 days = (1/5) roof / day

Homeowner + Contractor = (1/8) roof / day + (1/5) roof /day
= (13/40) roof / day

1 roof / ((13/40) roof/day) = 40/13 days = about 3.1

Thanks for the help.