A kind of schoolbag, if sold at 84 yuan each, can earn 20%. How much does each bag cost?
一种书包，如果按每个84元出售，则可赚20%．每个书包的成本是多少元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">84 / (6/5)</gadget>
<output>70</output>

<result>70</result>