A tourist bus travels on the plain and on the mountain road for 2 hours each, at a speed of 50 kilometers per hour on the plain and 30 kilometers per hour on the mountain, and finally reaches the top of the mountain. How long is this journey?
一辆旅游车在平原和山路各行驶了2小时，在平原行驶的速度是每小时50千米，在山区行驶的速度是每小时30千米，最后到达山顶．这段路程有多长？
<gadget id="calculator">50 + 30</gadget>
<output>80</output>

<gadget id="calculator">80 * 2</gadget>
<output>160</output>

<result>160</result>