The sum of the current ages of the elder brother and younger brother is 50 years old. When the elder brother is the younger brother's current age, the younger brother's age is half of the elder brother's age. How old is the elder brother now?
哥哥和弟弟现在的年龄和为50岁，当哥哥为弟弟现在的年龄时，弟弟的年龄为哥哥的一半，请问哥哥现在多少岁？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 50</gadget>
<output>25</output>

<gadget id="calculator">50 - 25</gadget>
<output>25</output>

<gadget id="calculator">50 + 25</gadget>
<output>75</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + 1 + (1/2)</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">75 / (5/2)</gadget>
<output>30</output>

<result>30</result>