22.5 minutes is one-half of 45 minutes. 45 minutes is three-quarters of an hour, half of three-quarters is three-eighths, so 22.5 minutes is three-eighths of an hour. Divide 9 miles by 3/8 hour, which is to say multiply 9 by 8/3 to get miles per hour (remember invert and multiply?). The rest is up to you.
John
My calculator said it, I believe it, that settles it
