A travels 9 kilometers per hour, and B travels 7 kilometers per hour. A travels south from Nanzhuang, while B travels north from Beizhuang. After 3 hours, the two were 60 kilometers apart. How many kilometers are there between the north and the south villages?
甲每小时行9千米，乙每小时行7千米，甲从南庄向南行，同时乙从北庄向北行．经过3小时后，两人相隔60千米．南北两庄相距多少千米？
<gadget id="calculator">9 + 7</gadget>
<output>16</output>

<gadget id="calculator">16 * 3</gadget>
<output>48</output>

<gadget id="calculator">60 - 48</gadget>
<output>12</output>

<result>12</result>