There are two boxes of apples, one box of apples weighs 18 kilograms, if 3 kilograms are taken out of the box, the two boxes of apples weigh the same, how much does the other box of apples weigh?
有两箱苹果，一箱苹果重18千克，如果从中取出3千克，两箱苹果就一样重，另一箱苹果重多少？
<gadget id="calculator">18 - 3</gadget>
<output>15</output>

<result>15</result>