Install street lamps on both sides of Changzheng Road, one every 20 meters. If both ends of the road have to be installed, a total of 152 lamps need to be installed. How long is the Long March Road in meters?
在长征路的两边装路灯，每隔20米装一盏．如果路的两端都要装，一共需要装152盏．长征路全长多少米？
<gadget id="calculator">152 / 2</gadget>
<output>76</output>

<gadget id="calculator">76 - 1</gadget>
<output>75</output>

<gadget id="calculator">20 * 75</gadget>
<output>1_500</output>

<result>1_500</result>