So Speed is equal to Distance traveled divided by total time
S = D/T
Since Frankie ran 2 miles in 15 minutes her speed is 2/15 or 0.13333 miles per minute while Bella ran 3 miles in 20 min which is 3/20 or 0.15 miles per minute. So 0.15 > than 0.133 and thus Bella ran faster.
