A certain unit held a Spring Festival tea party and bought 4 boxes of apples with the same weight. After removing 10 kilograms from each box, the sum of the weights of the remaining apples in each box was exactly equal to the weight of the original 3 boxes of apples. How many kilograms did each box weigh?
某单位举办迎春茶话会，买来4箱同样重的苹果，从每箱取出10千克后，各箱所剩的苹果重量之和，恰好等于原来3箱苹果的重量，原来每箱苹果重多少千克？
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>