The answer is: 
The explanation is shown below:
1- You have the following expression given in the exercise:

2- When you multiply signs, you obtain:

3. Now, you must add like terms, as following:

4. Therefore, you have that the expression simplified is:

8.5 is the same as 8.50, right? So just take the digit in the hundredth place of both decimals and subtract. You'd be doing 0-4 so you can go ahead and borrow a number to make 10-4, which equals 6. So without subtracting 8.5 and 4.64, you can determine that 6 will be in the hundredth place. Hope this helps!
845 miles / 13 hours = 65 miles per hour
65 miles per hour x 11 hours = 715 miles