The distance between A and B is 147 kilometers. Xiaohua and Xiaoming are walking toward each other from the two places at the same time. After meeting for 1.5 hours, the ratio of the speed of Xiaohua and Xiaoming is 3:4. Ask: How much longer is Xiaoming than Xiaohua when they meet? km?
甲、乙两地相距147千米，小华、小明同时从两地相向而行，经过1.5小时相遇，小华与小明速度的比是3：4，问：相遇时小明比小华多行多少千米？
<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">147 / 7</gadget>
<output>21</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">21 * 1</gadget>
<output>21</output>

<result>21</result>