salt factory produces an average of 2,100 kilograms of salt per day in the first 3 days, and a total of 13,300 kilograms of salt in the next 4 days. How many kilograms of salt does this salt factory produce on average every day this week?
一个制盐厂，前3天平均每天制盐0.21万千克，后4天共制盐1.33万千克．这个制盐厂这周平均每天制盐多少万千克？
<gadget id="calculator">0.21 * 3</gadget>
<output>0.63</output>

<gadget id="calculator">0.63 + 1.33</gadget>
<output>1.96</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">1.96 / 7</gadget>
<output>0.28</output>

<result>0.28</result>