I believe the answer is 3. Because if you have a ratio that is 2:1 and Evan has 6 then it would be 6:x and so you just divide two? I hope that is correct! :)
Charges 0.50 per mile with a 5 dollar surcharge. Spending at most 30 dollars, the equation would be:
0.5x+5
30
To find how many miles they can travel/the solution, solve the inequality:

Subtract 5 from both sides.

Divide both sides by 0.5.

They can travel (at most) 50 miles.
Hope this helps :)