Here's what you need to do:
We know that Ryan can install 100 square feet of flooring in 5 hours.
So, if we take 100 square feet, and divide by 5 hours, 100/5, we end up with 20, meaning Ryan can install 20 square feet of flooring every hour.
Then, simply multiply 20 by 40, 20*40, and you end up with 800.
Meaning, in 40 hours, Ryan can install 800 square feet of flooring.
Answer: 800 square feet.
