Two bags of colored balls, if 15 are taken out from the first bag and put into the second bag, then the colored balls in the second bag are exactly (5/7) of the first bag, the second bag originally had 25 colored balls, and the second bag contains 25 colored balls. How many colored balls are there in a bag?
两袋彩球，如果从第一袋取出15个放入第二袋，这时第二袋里的彩球正好是第一袋的(5/7)，第二袋原有25个彩球，第一袋里原有多少个彩球？
<gadget id="calculator">25 + 15</gadget>
<output>40</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">40 / (5/7)</gadget>
<output>56</output>

<gadget id="calculator">56 + 15</gadget>
<output>71</output>

<result>71</result>