Hello there! Given Dave only has $15 and the book is $8, we can assume he already paid for the book:
$15 - $8 = $7
Because Dave has $7 left, we can use the following inequality to show that he can spend up to $7 at maximum on both cards:
c = $7
Given Dave buys 2 cards, we can divide 7 by 2 to find how much Dave spends on each card:
7 divided by 2 gives us 3.50
Hence, Dave can spend $3.50 on each card.
Hope this helps!
