Beibei's family travels by car, traveling 64 kilometers per hour and arriving in 4.5 hours. If it takes 4 hours to arrive, how many kilometers per hour will it take?
贝贝一家自驾车旅游，每小时行驶64千米，4.5小时到达．如果要4小时到达，每小时要行驶多少千米？
<gadget id="calculator">64 * 4.5</gadget>
<output>288</output>

<gadget id="calculator">288 / 4</gadget>
<output>72</output>

<result>72</result>