The sum of the numbers A, B, and C is 140. The number of A is twice the number of B, and the number of B is twice the number of C. What is the number of C?
甲、乙、丙3个数的和是140，甲数等于乙数的2倍，乙数是丙数的2倍，丙数是多少？
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 2 + 1</gadget>
<output>7</output>

<gadget id="calculator">140 / 7</gadget>
<output>20</output>

<result>20</result>