Xiao Ming participates in basketball training in the gymnasium. If he goes there by car and walks home, it will take 45 minutes on the way;
小明在体育馆参加篮球训练，如果去时坐车，回家时走路，在路上需花45分钟；如果往返都坐车只需15分钟；如果往返都步行，则需要多少分钟．
<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">45 - (15/2)</gadget>
<output>75/2 = around 37.5</output>

<gadget id="calculator">(75/2) * 2</gadget>
<output>75</output>

<result>75</result>