The elder brother has 8.5 yuan. After he gives the younger brother 1.7 yuan, the two have the same amount. How much is the younger brother?
哥哥有8.5元，他给弟弟1.7元后，两人同样多，弟弟原有多少钱？
<gadget id="calculator">1.7 * 2</gadget>
<output>3.4</output>

<gadget id="calculator">8.5 - 3.4</gadget>
<output>5.1</output>

<result>5.1</result>