The cafeteria bought 840 kilograms of rice. If an average of 40 kg is used per day, how many weeks can the rice be used for?
食堂买来大米840千克．如果平均每天用去40千克，这些大米可以用多少个星期？
<gadget id="calculator">840 / 40 / 7</gadget>
<output>3</output>

<result>3</result>