A boat traveled upstream a distance of 90 miles at an average speed of (v-3) miles per hour. It then traveled the same distance downstream at a average speed of (v+3) miles per hour. If the trip upstream took half an hour longer than the trip downstream, how many hours did it take to make the trip downstream?
The way I tried to solve this problem was by setting (90)/(v-3) = (90)/(v+3) + 0.5. Then, I can solve for v but that would take a long time. I could also use the answer choices to solve for v, and then test it using the equation but that seems to take just as long. Is there a better way?