Dave has $15 to spend on an $8 dollar book and two birthday cards (c) for his friends. how much can he spend on each card if he buys the same card for each friend?

If Dave has 15 dollars and must spend 8 dollars of it on a book, then he will have 7 dollars left. If he then buys two of the same cards for his friends, the most he will be able to spend is half of 7 dollars for each of them, which will be 3 dollars and 50 cents. 

Agreed i also had the same answer