The two brothers took a total of 200 yuan to the bookstore to buy reference materials. After returning home, they had exactly the same amount of money left. It is known that the elder brother spent his own money to count (3/7), and the younger brother spent his own money to count (7 /9), how much did my brother spend?
兄弟二人共带200元去书店买参考资料，回家后两人剩下的钱数正好相等，已知哥哥花去自己钱数的(3/7)，弟弟花去自己钱数的(7/9)，哥哥花去多少元．
<gadget id="calculator">18 + 7</gadget>
<output>25</output>

<gadget id="calculator">7 / 25</gadget>
<output>7/25 = around 0.28</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">200 * (7/25) * (3/7)</gadget>
<output>24</output>

<result>24</result>