Answer:
After 5 months each company will charge the same amount
Explanation:
Math Modeling
The situation raised in the question can be modeled as follows.
Company A charges $75 upfront (flat or fixed fee) plus $20 a month. Being x the number of months of subscription, the total charge Ca is:
Ca = 75 + 20x
Company B charges no upfront fees, and $35 a month. We model its charges Cb as:
Cb = 35x
We want to know the number of months needed to make both companies charge the same amount. We'll do that by equating Ca=Cb:
75 + 20x = 35x
Subtracting 20x:
75 = 35x - 20x
Swapping and simplifying:
15x = 75
Solving:
x=75 / 15
x=5
After 5 months each company will charge the same amount