Since 2 goes into 8, you would simplify. You would get 1 inch and 4 miles. Next, set up a ratio. The ratio is 1 inch: 4 miles. So for every inch on the map, there is 4 miles.
The answer is B, because you will have to multiple 42 by 7 to see how much money he will have in 7 weeks and then you will have to subtract 8 × 8.25 to see how much money he spent on his vacation.