Please help with this question: The speed r (in mph) to which a car can accelerate in t seconds can be described by r(t) = -0.15t^2 + 6.75t + 13.75, 0 < t < 25. How long does it take the car to accelerate to 60 mph?

I'm not certain if I solved this correctly, but I set up the equation as

60 = -0.15t^2 + 6.75t + 13.75, and ended up with t = 8.432 and t = 36.568 when I solved it as a quadratic. If this is correct, would both solutions be answers to this problem?