The average of the three numbers A, B, and C is 70, A: B = 2: 3, B: C = 3: 5, then what is the number of B?
甲、乙、丙三个数的平均数是70，甲：乙=2：3，乙：丙=3：5，则乙数是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">1 + (2/3) + (5/3)</gadget>
<output>10/3 = around 3.333333</output>

<gadget id="calculator">210 / (10/3)</gadget>
<output>63</output>

<result>63</result>