12 yuan is enough to buy 24 ballpoint pens, or 40 pencils. Now we need to buy the same amount of the two types of pens, and we need to use up the money. How many of the two types of pens can we buy? (Answer in two ways.
12元钱，够买24支圆珠笔，或40支铅笔，现在两种笔要买同样多，并且要把这笔钱用完，两种笔各能买多少支？(用两种方法解答．
<gadget id="calculator">12 / 24</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">12 / 40</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/2) + (3/10)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">12 / (4/5)</gadget>
<output>15</output>

<result>15</result>