The elder brother has 100 yuan and the younger brother has 80 yuan. After how much money the elder brother gives to the younger brother, the ratio of money between the two brothers is 7:11.
哥哥有100元钱，弟弟有80元，哥哥给弟弟多少元钱后兄弟两人的钱数比是7：11．
<gadget id="calculator">100 + 80</gadget>
<output>180</output>

<gadget id="calculator">7 + 11</gadget>
<output>18</output>

<gadget id="calculator">11 / 18</gadget>
<output>11/18 = around 0.611111</output>

<gadget id="calculator">180 * (11/18)</gadget>
<output>110</output>

<gadget id="calculator">110 - 80</gadget>
<output>30</output>

<result>30</result>