What is the probability of drawing a red ball in a box containing 9 red balls and 15 black balls?
在一个装有9个红球和15个黑球的盒子里，摸到红球的可能性是多少．
<gadget id="calculator">9 + 15</gadget>
<output>24</output>

<gadget id="calculator">9 / 24</gadget>
<output>3/8 = around 0.375</output>

<result>3/8 = around 0.375</result>