Answer:
3.6 miles
Explanation:
For a trip of x miles, there are x-0.5 miles of it that are "additional", which makes (x-0.5)/0.1 additional tenths.
Then the charges (in dollars) are ...
... 3.50 + 0.30(x -0.5)/0.1
Adding a tip of $2 and requiring the total be less than $15 gives ...
... 3.50 + 0.30(x -0.5) + 2.00 ≤ 15.00
... 5.50 + 3(x - 0.5) ≤ 15.00 . . . . simplify a bit
... 4.00 +3x ≤ 15.00 . . . . . . . . . . simplify more
... 3x ≤ 11.00 . . . . . . subtract 4.00
... x ≤ 3.667 . . . . . . divide by 3
Miles are measured in tenths. We cannot go 3.7 miles on $15, but we can go 3.6 miles.