There are several apples and pears, and the number of apples is three times the number of pears. If you eat 2 pears and 5 apples every day, then there will be 20 apples left after eating the pears. How many pears are there?
有若干个苹果和梨，苹果的个数是梨的个数的3倍，如果每天吃2个梨和5个苹果，那么梨吃完时还剩20个苹果，有多少个梨．
<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">4 / (1/10)</gadget>
<output>40</output>

<result>40</result>