Teacher Luo made a simple balancer, the left and right sides of the midpoint are 8 decimeters long. Mr. Luo hung a 40-kilogram object at the midpoint of the left distance 3 decimeters, and Li Xin hung an object of how many kilograms at the extreme point on the right, so that the left and right sides can be balanced.
罗老师做了一个简易平衡器，中点左右两边都有8分米长．罗老师在左边距中点3分米处挂了一个40千克的物体，李鑫在右边最端点处挂一个多少千克的物体，左右两边才能平衡．
<gadget id="calculator">3 * 40</gadget>
<output>120</output>

<gadget id="calculator">120 / 8</gadget>
<output>15</output>

<result>15</result>