The milk production of the three cows raised by Zhang Yan last week was 661.5 kilograms. How many kilograms of milk does each cow produce on average per day?
张燕家养的3头奶牛上周的产奶量是661.5千克，平均每头牛一天产奶多少千克？
<gadget id="calculator">661.5 / 7 / 3</gadget>
<output>31.5</output>

<result>31.5</result>