Xiao Ming's running speed is three times faster than walking. He walks from home to school every day. One day, because he started 5 minutes late, he had to walk half of the distance and run for the other half. This is exactly the same as the usual arrival time , Then, how many minutes does it take Xiao Ming to walk to school every day?
小明跑步的速度是步行的3倍，他每天从家到学校都是步行，有一天由于晚出发了5分钟，他不得不步行一半路程后，另一半路程要跑步，这样与平时到达时间正好一样，那么，小明每天步行上学需要多少分钟．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) * 3 * 2</gadget>
<output>15</output>

<result>15</result>