An automobile is traveling at 65 mph. If each tire has a radius of 15 inches, at which rate are the tires spinning in revolutions per minute (rpm)? (63360in=1 mile)

Answer 1

i did
65 miles=1 hour
63360 in=1 mile
1 hour= 60 minutes
1 rev=30 pi
in the end after multiplying i got 728.3 rpm, is this correct?

Answer 2

One rotation = 30π inches, you had that

65 miles per hour
= 65(63360) inches per 60 minutes
= 68640 inches/min

number of rotations = 68640/(30π)
= 728.3 rotations

correct!!!