Hey there!
1.) For this, since you know that your speed is 65 mph, you drive 65 miles every hour. Given that you drive 643 miles at this speed, to find this, you must divide the number of miles by the rate (Time=Distance/Rate). This would be represented by this expression:
643/65
When simplified, you get approximately 9.9 hours, which would be choice A.
2.) For this problem, you would use the same formula, Time=Distance/Rate.
Since you already know the distance is 720 miles and the rate is 60mph, set up this expression: 720/60
When you simplify, you should get 12, which would be choice B.
