Question

How many hours did it take him to finish the project?

Answer 1

First, find 20% of 5 hours. 20% is also 1/5 of something, and 1/5 of 5 is 1. 
Multiply 5 by 3 for the 300%, getting 15 hours, and add 1 for the 20%. 
He spent 16 hours on the project. Hope this helps!