ROSS bought classic comic books for 10 each. When the price increased to $17 per book, he sold all of his comic books except one. His profit was $49. How many comic books did Ross buy? Explain how you found the answer.

x = number of comics Ross bought

A = 10*x = amount spent on buying those x number of comics at $10 each

B = 17 * (x-1) = amount Ross gets from selling every comic book except one

B-A = 17 * (x-1) - 10x = 7x-17 = profit = 49

7x-17 = 49

7x = 49+17

7x = 66

x = 66/7

x = 9.42857 approximately

Because x isn't a whole number, I'm thinking that there's a typo in the problem somewhere. I would double check with your teacher.