Uncle Zhang rented a fruit warehouse at a monthly rent of 600 yuan and stored 2.4 tons of fruit. By convention, these fruits need to be sold for two months. As a result of lowering the sales price, it was sold out in one month. Due to the savings in rent, after the settlement, I earned an extra 120 yuan. How much is it lower than planned per kilogram of fruit in sales?
张叔叔以每月600元的租金租用了一个果品仓库，存放进去2.4吨水果．按照惯例，这些水果需销售两个月．由于降低了销售价格，结果一个月就销售完了．由于节省了租金，结算下来，反而多赚了120元．销售时每千克水果比计划降低了多少元？
<gadget id="calculator">600 - 120</gadget>
<output>480</output>

<gadget id="calculator">2.4 * 1_000</gadget>
<output>2_400</output>

<gadget id="calculator">480 / 2_400</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>