Answer:
$ 0, according to the information given.
Step-by-step explanation:
1. Let's review the information given to us to answer the question properly:
Fee for the rental of the truck = $ 70
Additional fee for mile driven = $ 0 or not informed
Miles driven during the day = 100
2. What is the slope?
Since there is no additional charge per mile driven or not informed, the slope is zero.