Xiao Li bought several apples at the price of 3 apples for 1 yuan, and sold 5 apples at 2 yuan. How many apples should he sell if he wants to earn a profit of 10 yuan.
小李以1元钱3个苹果的价格买进若干个，又以2元5个卖出．若他要赚得10元钱利润他应卖多少个苹果．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(2/5) - (1/3)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">10 / (1/15)</gadget>
<output>150</output>

<result>150</result>