Question 985215

Jerry had a doctor's appointment at 10:00 am. The doctor's office is located 16.2 miles away from Jerry's house. John got in the car at 9:30 am, drove with an average speed of 25.4 mph.
Jerry ended up being late for the appointment. How much faster should he have driven (in mph).
<pre>{{{Speed = Distance/Time}}}
Time to get there: 30 minutes, or {{{1/2}}} hour
Speed at which he needs to drive to get there in exactly 30 minutes: {{{Speed = 16.2/(1/2)}}}, or 32.4 mph
Actual speed he traveled at to get there late: 25.4 mph. 
So, he should've travelled at least {{{highlight_green(7)}}} (32.4 - 25.4) mph faster to get there in EXACTLY 30 minutes, or {{{1/2}}} hour