From A to B is an uphill road, and from B to C is a downhill road. Wang Yan passed through B to C from A, and then immediately returned to A along the same road. It took 3.5 hours. It is known that Wang Yan's uphill speed is the same, and her downhill speed is also the same, and the time spent on the uphill road is 0.5 hours longer than that on the downhill road. Then, how many hours did Wang Yan spend on the uphill road?
从甲地到乙地是上坡路，从乙地到丙地是下坡路，王燕同学自甲地途经乙地到丙地，立即再沿原路返回甲地，共用3.5小时．已知王燕上坡速度相同，下坡速度也相同，并且走上坡路所用时间比走下坡路所用时间多0.5小时，那么，王燕走上坡路共用了多少小时．
<gadget id="calculator">3.5 - 0.5</gadget>
<output>3</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">0.5 + (3/2)</gadget>
<output>2</output>

<result>2</result>