Students from classes A and B visit the airport 24 kilometers away from the school. There is a car that can only take students from one class at a time. In order to arrive at the airport as soon as possible, the two classes agreed that Class A will take the car first, and Class B will walk first, and start at the same time. It is known that Class A and Class B walk at the same speed, and the speed of the car is 7 times faster than that of walking. Ask how many kilometers away from the airport the car should return to pick up the students of class B so that the students of the two classes can arrive at the airport at the same time.
甲、乙两班学生到离校24千米的飞机场参观，有一辆汽车，一次只能乘坐一个班的学生．为了尽快地到达机场，两个班商定，由甲班先坐车，乙班先步行，同时出发，甲班学生在中途下车步行去飞机场，汽车立即返回接在途中步行的乙班学生．已知甲、乙班步行速度相同，汽车的速度是步行的7倍．问汽车应在距机场多少千米处返回接乙班学生，才能使两班学生同时到达机场．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">1 + 3 + 1</gadget>
<output>5</output>

<gadget id="calculator">24 / 5</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>