Given the following reasoning and answer, what was the question? 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 answer: 30

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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The question 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?