The school cafeteria carried out the "Water Conservation Week" activity, saving an average of 1.8 tons of water per day in the first 3 days, and saving a total of 4 tons of water in the next 2 days. How many tons of water did you save on average per day this week? ．
学校食堂开展"节约用水周"活动，前3天平均每天节约用水1.8t，后2天共节约用水4t．这周平均每天节约用水多少吨？．
<gadget id="calculator">1.8 * 3</gadget>
<output>5.4</output>

<gadget id="calculator">5.4 + 4</gadget>
<output>9.4</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">9.4 / 5</gadget>
<output>1.88</output>

<result>1.88</result>