Put 15 red and blue pencils in the pocket. If you touch any one, how many red pencils should you put in your pocket so that the probability of touching a blue pencil is (2/5)?
在口袋里放红、蓝铅笔一共15枝．任意摸一枝，要使摸到蓝铅笔的可能性是(2/5)，口袋里应放多少枝红铅笔？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">15 * (3/5)</gadget>
<output>9</output>

<result>9</result>