Distance = speed * timesud21 wrote:
Let the time taken = T
Then for slower trip, S * (T + 1) = 450... Equation 1
For faster trip, (S + 5) * T = 450... Equation 2
So, S * (T + 1) = (S + 5) * T
ST + S = ST + 5T or S = 5T
Putting S = 5T in Equation 1, we get 5T(T + 1) = 450
5T² + 5T - 450 = 0
T² + T - 90 = 0
T² + 10T - 9T - 90 = 0
(T - 9)(T + 10) = 0 implies T = 9
Therefore, S = 5 * 9 = 45 miles per hour
The correct answer is C.
