Answer:
The total charge at Gym A and Gym B would be the same at 6 months
Explanation:
The model for the charges of both Gyms is made of the registration fee plus a variable quantity per month.
Let's call m the number of months for members.
Gym A charges $74 plus $33 per month, thus:

Gym B charges $164 plus $18 per month, thus:

We want to find out the number of months needed for both charges to be the same, thus:

Subtracting 74 and 18m:

Simplifying:

Dividing by 15:

m=6
The total charge at Gym A and Gym B would be the same at 6 months