certain sporting goods store has bought a batch of basketballs, which are divided into first-grade crystals and second-grade products. The purchase price of the second-grade crystal is 20% cheaper than that of the first-grade crystal. The first-grade product is priced at a 20% profit margin, and the second-grade product is priced at a 10% profit margin. The first-grade product is 16 yuan more expensive than the second-grade product. Ask the first-grade product How much is the purchase price of basketball?
某体育用品商店进了一批篮球，分一级晶和二级品．二级晶的进价比一级晶便宜20%，一级品按20%的利润率定价，二级品按10%利润率定价，一级品比二级品贵16元，问一级品的篮球进价是多少元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/5) * (1/10)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/50) - 1 - (1/10)</gadget>
<output>-27/25 = around -1.08</output>

<gadget id="calculator">1 + (1/5) + (1/5) + (-27/25)</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">16 / (8/25)</gadget>
<output>50</output>

<result>50</result>