Tom goes to a combined undergrad and Ph.D. program. It takes 3 years to finish the BS and 5 years to finish the Ph.D. Tom finishes it in 3/4ths the time. How long does it take for him to finish? Let's be accurate as possible.

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.
user
The program normally takes 3 + 5 = 8 years. So he manages to finish in 8 * 3 / 4 = 6 years.
The answer: 6.