John is collecting vintage baseball cards

Question

and has about 25 he got from his dad. He is collecting about 2 cards per month. Write a function, C(x), that represents how many cards John has after x months.

Answer 1

About means to me 1.5 to 2.5 cards, varying over time , so I would model this as

How many cards he has = starting number of cards (25) + (1.5 number of months) minimum

= starting number of cards(25) + (2.5 number of months) maximum

Answer 2

C(x) = 25 + 2x