Which speed is the fastest?
Answer:
1 yard = 3 feet
I. Speed = 18 feet/ 20 minute = 0.9 feet/minute
II. Speed = 20*3 feet/ 90 minute = 0.6667 feet/minute [1.5 hours = 90 minutes]
III. Speed = 11 feet/ 15 minute = 0.7333 feet/ minute
So, first one is the fastest