The number of A is 43, which is 13 more than twice the number of B. What is the number of B?
甲数是43，比乙数的2倍还多13，乙数是多少？
<gadget id="calculator">43 - 13</gadget>
<output>30</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>