Sally teaches elementary school and is given $320 to spend on books for her students. A reading book costs $12 and there are 30 students in her class. Unfortunately, if the money she is given by the school to pay for books is not sufficient, she will need to pay the rest out of pocket. How much money does Sally need to pay out of pocket, to buy every student a reading book? Let's be accurate as possible.
To purchase a book for each student, Sally needs: 30 x $12 = $360. She thus needs to pay $360 - $320 = $40 out of pocket.
The answer: 40.