A tourist bus travels at a speed of 50 km/h on a plain and at a speed of 30 km/h on a mountain; it travels on the plain and the mountain for 2 hours each, and finally reaches the top of the mountain. How long is this journey?
一辆旅游车在平原行驶的速度是50千米/时，在山区行驶的速度是30千米/时；在平原和山区各行了2小时，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>