Give the step-by-step reasoning process and then the final answer. Together Felipe and Emilio needed a combined time of 7.5 years to build their homes. Felipe finished in half the time of Emilio. How many months did it take Felipe to build his house?
Let F = the number of years Felipe needed to build his house. Emilio = 2F. 3F = 7.5 years. F = 2.5 years. 2.5 years = 30 months. It took Felipe 30 months to build his house.
The final answer: 30.