1. The problem statement, all variables and given/known data Driving to a nearby city, a motorist estimates his travel time, considering that he can maintain a constant velocity of 90km/h. Surprised by an unexpected rain shower, he decides to reduce his velocity to 60km/h until it stops raining 15 minutes later, at which time he returns to his original velocity. This temporary reduction in speed increases his travel time, in relation to his original estimate by how much: a) 5 minutes b) 7.5 minutes c) 10 minutes d) 15 minutes e) 30 minutes 2. Relevant equations D=vt (I think that's all really) 3. The attempt at a solution I know that, because of the rain, the driver drove 15 km at the reduced speed of 60km/h (which was also for a duration of 15 minutes) but when I actually try to do the problem I can't seem to get the right answer. The funny thing is I've done this question before and got the correct answer easily.