Answer:
D) 7.50 + p = 9.50
Explanation:
We know that the book is $7.50.
We also know that the total cost is $9.50.
This means that when buying the book and the pen, the total cost will be $9.50.
So $7.50(the cost of the book) plus the cost of the pen should equal to $9.50.
If p = the cost of the pen
$7.50 + p = $9.50
Also, using algebra, we can minus $7.50 from $9.50 to find the cost of the pen.