There are three boxes of black and white balls, each box contains 60 balls, the number of white balls in the first box is the same as the number of black balls in the second box, and 25% of the balls in the third box are white balls. How many white balls are there in all three boxes?
有三盒黑白皮球，每盒60个，第一盒里白皮球和第二盒里的黑皮球个数同样多，第三盒里的25%是白皮球．这三个盒子里一共有多少个白皮球？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">60 * (1/4)</gadget>
<output>15</output>

<gadget id="calculator">60 + 15</gadget>
<output>75</output>

<result>75</result>