Answer: 14 pens
Explanation:
In order to solve this equation you first need to subtract 8 from 15 since the $8 was already used. So after we subtract we can conclude that Ezekiel has $7 left to spend on pens. To figure out how many pens Ezekiel can buy you would use the equation 0.50p=7 you would solve for p, and you would then get 14.