The answer is A. 1,032 miles.
You divide 42 gallons by 7. This is because you know how many miles can be reached per 7 gallons.
41
172
x 6
------
1032
When you divide 42/7 you get 6. You then take 6 and multiply it by 172. 6x2 is 12, you carry the one, 6x7 is 42, plus the 1 that you carried, so you get 43, you carry the 4, 6x1 is 6, and you add the 4 to get 10. This brings your answer to 1, 032.