Two road repairing teams simultaneously build a 78-kilometer road from both ends. Team A repairs an average of 2.4 kilometers per day, and Team B repairs an average of 2.8 kilometers per day. How many days will it take to complete the road?
两个修路队从两端同时修一条78千米的公路，甲队平均每天修2.4千米，乙队平均每天修2.8千米，多少天能修完这条公路？
<gadget id="calculator">2.4 + 2.8</gadget>
<output>5.2</output>

<gadget id="calculator">78 / 5.2</gadget>
<output>15</output>

<result>15</result>