The ratio of the two numbers of A and B is 7:3, and the number of A is 36 more than the number of B. What is the number B.
甲乙两数的比是7：3，甲数比乙数多36．乙数是多少．
<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<result>27</result>