The average of the three numbers A, B, and C is 60, and the ratio of the three numbers is (1/2):(1/3):(1/6), and the number B is less than the number A.
甲、乙、丙三个数的平均数是60，三个数的比是(1/2)：(1/3)：(1/6)，乙数比甲数少多少．
<gadget id="calculator">3 + 2 + 1</gadget>
<output>6</output>

<gadget id="calculator">3 / 6</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">60 * 3 * (1/2)</gadget>
<output>90</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">60 * 3 * (1/3)</gadget>
<output>60</output>

<gadget id="calculator">90 - 60</gadget>
<output>30</output>

<result>30</result>