The ratio of the three numbers A, B, and C is 2:5:8. The average of the three numbers is 45. What is the number C?
甲、乙、丙三个数的比是2：5：8，三个数的平均数是45，丙数是多少．
<gadget id="calculator">45 * 3</gadget>
<output>135</output>

<gadget id="calculator">2 + 5 + 8</gadget>
<output>15</output>

<gadget id="calculator">8 / 15</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">135 * (8/15)</gadget>
<output>72</output>

<result>72</result>