Cars A and B start from point A, and a horse-drawn carriage starts from point B at the same time, and they drive towards each other. After 5 hours, they meet car A, and after 6 hours, they meet car B. It is known that car A travels 20 kilometers per hour, and car B travels toward each other. The carriage travels 16 kilometers per hour. May I ask: How many kilometers per hour does the carriage travel?
甲、乙两车从A地，一辆马车从B地同时出发，相向而行，5小时后遇到甲车，6小时后遇到乙车，已知甲车每小时行20千米，乙车每小时行16千米，请问：马车每小时行多少千米？
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">16 * 6</gadget>
<output>96</output>

<gadget id="calculator">100 - 96</gadget>
<output>4</output>

<gadget id="calculator">6 - 5</gadget>
<output>1</output>

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

<result>4</result>