A certain unit of the People's Liberation Army dispatched 80 vehicles to participate in construction site labor, passing through a 120-meter-long tunnel on the way. If the length of each car is 10 meters and the distance between two adjacent cars is 20 meters, how many minutes will it take for the convoy to pass through the tunnel at a speed of 500 meters per minute?
解放军某部出动80辆汽车参加工地劳动，在途中要经过一个长120米的隧道．如果每辆汽车的长为10米，相邻两辆汽车相隔20米，那么，车队以每分钟500米的速度通过隧道，需要多少分钟？
<gadget id="calculator">10 * 80</gadget>
<output>800</output>

<gadget id="calculator">80 - 1</gadget>
<output>79</output>

<gadget id="calculator">20 * 79</gadget>
<output>1_580</output>

<gadget id="calculator">120 + 800 + 1_580</gadget>
<output>2_500</output>

<gadget id="calculator">2_500 / 500</gadget>
<output>5</output>

<result>5</result>