15 same glass balls are packed in one empty box, the total weight of the box is 125 grams, and 20 glass balls are packed in two same empty boxes, and the total weight of the box is 170 grams. How many grams does one glass ball weigh?
用一个空盒装同样的玻璃球15个，连盒共125克，用两个同样的空盒装20个玻璃球连盒共重170克，一个玻璃球重多少克？
<gadget id="calculator">170 - 125</gadget>
<output>45</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<gadget id="calculator">45 / 5</gadget>
<output>9</output>

<result>9</result>