Pack a bunch of balls into four boxes, among which (1/3) is put into box A, (1/5) is put into box B, and the balls put into box C are 75% of the total number of balls in box A and box B. Put 4 balls in the box. How many balls are there in this pile?
把一堆皮球分装在四个盒子里，其中(1/3)放入甲盒，(1/5)放人乙盒，放人丙盒的皮球是甲、乙盒皮球总数的75%，丁盒放入4个皮球．这堆皮球一共有几个？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/3) + (1/5)</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(8/15) * (3/4)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/3) - (1/5) - (2/5)</gadget>
<output>1/15 = around 0.066667</output>

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

<result>60</result>