Car A travels 30 kilometers per hour when it goes to place B to deliver goods, and arrives in 4.5 hours. When it returns, it takes an extra 1.5 hours to return to place A due to headwinds. How many kilometers does this car travel per hour when it returns? (Solved by both equations and arithmetic)
甲车去乙地送货去时每小时行30千米，4.5小时到达，返回时由于逆风多用了1.5小时才返回甲地，这辆车返回时每小时行多少千米？(用方程和算术两种方法解)
<gadget id="calculator">30 * 4.5</gadget>
<output>135</output>

<gadget id="calculator">4.5 + 1.5</gadget>
<output>6</output>

<gadget id="calculator">135 / 6</gadget>
<output>45/2 = around 22.5</output>

<result>45/2 = around 22.5</result>