2/3 of an hour equals 40 minutes, so 19 1/2 miles is 40 minutes. 20 minutes is 1/3 of an hour, which is the missing amount of 2/3. Divide 19 1/2 miles by 2 to get 9 3/4 miles (which is how far Ms. Sanchez can go in 20 minutes). multiply by 3 to get 29 1/4 Miles Per Hour.
