There are three natural numbers, the ratio of number A to number B is 3:5, the ratio of number B to number C is 4:7, and the sum of the three numbers is 201. Then what is the number of A?
有三个自然数，甲数与乙数的比是3：5，乙数与丙数的比是4：7，三个数的和是201．则甲数是多少．
<gadget id="calculator">12 + 20 + 35</gadget>
<output>67</output>

<gadget id="calculator">12 / 67</gadget>
<output>12/67 = around 0.179104</output>

<gadget id="calculator">201 * (12/67)</gadget>
<output>36</output>

<result>36</result>