The price of schoolbags is 15 yuan each, and the price of pencil cases is 8 yuan each. The sum of the prices of schoolbags and pencil boxes is 5 yuan less than 7 times the price of ballpoint pens. How much is the price of each ballpoint pen? (Solution of column equation)
书包每个售价15元，文具盒每个8元，书包和文具盒的售价总和比圆珠笔售价的7倍少5元．圆珠笔每枝售价多少元？(列方程解)
<gadget id="calculator">5 + 8 + 15</gadget>
<output>28</output>

<gadget id="calculator">28 / 7</gadget>
<output>4</output>

<result>4</result>