The average of the three numbers A, B, and C is 50, the number of A is 60, the ratio of the number B to the number C is 5:4, what is the number B?
甲、乙、丙三个数的平均数是50，甲数是60，乙数和丙数的比是5：4，乙数是多少．
<gadget id="calculator">50 * 3</gadget>
<output>150</output>

<gadget id="calculator">150 - 60</gadget>
<output>90</output>

<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">90 * (5/9)</gadget>
<output>50</output>

<result>50</result>