Question

Davie and Horatio are riding their motorbikes on a scenic tour that is 80 miles long. Davie rides at 20 miles per hour and leaves 90 minutes before Horatio. How fast must Horatio ride to finish at the same time as Davie?

Answer 1

distance = rate*time

For Davie, plug in distance = 80 miles and rate = 20 mph and solve for t. That’s how many hours it’ll take Davie to get there.

Now, Horatio must travel the same distance except he has 90 minutes (or 1.5 hours) less than Davie. So take Davies time in hours, subtract 1.5, to get t for Davie. Then plug in d = 80 miles and solve for r.