Tina is getting $20 for each book she sells. If she realizes a $120 profit on her sales, how many people have she sold the books to if each book costs $5 to make and every customer buys 2 at a time?
First, we need to determine the profit per book. To do this, we perform 20-5=
<gadget id="calculator">20-5</gadget>
<output>15</output>
15 dollars in profit per book.
Next, we divide the total sales by the profit per book, performing 120/15=
<gadget id="calculator">120/15</gadget>
<output>8</output>
8 books sold in total.
Since the books are sold 2 at a time, we divide the number sold by 2 to find the total number of people sold to, performing 8/2=
<gadget id="calculator">8/2</gadget>
<output>4</output>
4 people in total.

<result>4</result>