tourist bus traveled the plain and the mountain for 2 hours each, and finally reached the top of the mountain. It is known that a tourist bus travels 50 kilometers per hour in plains and 30 kilometers per hour in mountainous areas. How long is this journey?
一辆旅游车在平原和山区各行了2小时，最后到达山顶．已知旅游车在平原每小时行50千米，山区每小时行30千米．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>