.
There are two ways to solve this problem : one stupid way using inverse function,
and another MUCH more reasonable way using common sense.
Of these two ways, I prefer and will use the common sense solution.
The distance traveled by the bus over first 5 kilometers, is
= = 100 kilometers.
To it, I should add first 5 kilometers for 10 pesos. Doing it, I get the ANSWER :
+----------------------------------------------+
| With the given budget, the traveler can |
| reach as far as 100+5 = 105 kilometers. |
+----------------------------------------------+
Solved.
You will learn much more about solving this problem, if you apply
the simple way and will not create artificial difficulties to yourself.