There are 10 white balls, 3 red balls and 4 yellow balls in a box (the size and shape of the three balls are exactly the same), if you draw a ball at random, what is the probability of getting a red ball?
盒子里有10个白球，3个红球和4个黄球(三种球的大小和形状完全相同)，任意摸出一球，摸到红球的可能性是多少．
<gadget id="calculator">10 + 3 + 4</gadget>
<output>17</output>

<gadget id="calculator">3 / 17</gadget>
<output>3/17 = around 0.176471</output>

<result>3/17 = around 0.176471</result>