Rent a warehouse to store 3 tons of goods, and the monthly rent is 4,000 yuan. As usual, these goods need to be sold for two months, but because the boss lowered the price to sell them, they were sold out in one month, thus saving the rent. After settlement, I made an extra 1,600 yuan. How much is the price reduction per kilogram of goods?
租用仓库存放3吨货物，每月租金4000元．按惯例这些货物要销售2个月，由于老板降低价格出售，结果一个月就销售完了，因此节省了租金．一结算，反而多赚了1600元，每千克货物降价多少元？
<gadget id="calculator">4_000 - 1_600</gadget>
<output>2_400</output>

<gadget id="calculator">3 * 1_000</gadget>
<output>3_000</output>

<gadget id="calculator">2_400 / 3_000</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>