Answer:
5
Step-by-step explanation:
The slope will be the constant amount that the cost increases by each month.
In this situation, 5 is the slope, because he has to pay $5 each month.
35 is not the slope, and is instead the y intercept. This is because this is the cost at 0 months, since it is the membership fee.
So, the correct answer is 5.
It is rational because it is a terminating decimal. It can be represented as a ratio of two integers (121/10)