Chen rode his skateboard 3 3/4 miles in 3/4 of an hour. What is his average speed in miles per hour?
To find the average speed, we need to divide the distance by the time taken.
Distance = 3 3/4 miles = 15/4 miles
Time = 3/4 hour
Average speed = Distance / Time
Average speed = (15/4) / (3/4)
Average speed = (15/4) * (4/3) (dividing by a fraction is the same as multiplying by its reciprocal)
Average speed = 15 / 3
Average speed = 5 miles per hour
Therefore, Chen's average speed is 5 miles per hour.