A car transports a batch of supplies to a mountainous area. A total of 105 kilometers in the first 3 hours, and an average of 42 kilometers per hour in the next 5 hours. How many miles per hour does the car travel on average?
一辆汽车运送一批物资到山区．前3小时共行105千米，后5小时平均每小时行42千米．这辆汽车平均每小时行多少千米？
<gadget id="calculator">42 * 5</gadget>
<output>210</output>

<gadget id="calculator">105 + 210</gadget>
<output>315</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">315 / 8</gadget>
<output>315/8 = around 39.375</output>

<result>315/8 = around 39.375</result>