Sammy can paint the house by himself in 15 hours. With Nolan's help, it only takes 9 hours.
How long would it take for Nolan to paint the house by himself?

Given:

Sammy can paint the house by himself in 15 hours. With Nolan's help, it only takes 9 hours.

We need to determine the time it would take for Nolan to paint the house by himself.

Time taken by Nolan:

Let the rate that Sammy can paint the house by himself is

The rate that Sammy and Nolan together paint the house is

To determine the rate that it takes for Nolan to paint the house by himself is to subtract the rates.

Thus, we have;

Thus, the rate that it would take Nolan to paint the house by himself is

The time that it takes for Nolan to paint the house by himself can be determined using the formula,

Substituting the values, we have;

Thus, Nolan takes 22.5 hours to paint the house by himself.

1. perpendicular

2. parallel

3. perpendicular