Qiangqiang goes to grandma's house, if he walks back and forth, it will take 90 minutes. If he walked when he went, he took a car for 58 minutes when he came back. How many minutes will the ride take when he returns?
强强去外婆家，如果他来回都步行要用90分钟．如果他去时步行，回来时乘车一共用了58分．他回来时乘车要用多少分钟？
<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<gadget id="calculator">58 - 45</gadget>
<output>13</output>

<result>13</result>