If it costs 8.5 yuan to buy 5 ballpoint pens and 3 diaries, and 5.5 yuan to buy 3 ballpoint pens and 2 diaries, how much does it cost to buy 16 ballpoint pens and 10 diaries?
若买5支圆珠笔和3本日记本需8.5元，买3支圆珠笔和2本日记本需5.5元，则买16支圆珠笔，10本日记本需多少元．
<gadget id="calculator">8.5 * 2</gadget>
<output>17</output>

<gadget id="calculator">5.5 * 3</gadget>
<output>16.5</output>

<gadget id="calculator">17 - 16.5</gadget>
<output>0.5</output>

<gadget id="calculator">0.5 * 16</gadget>
<output>8</output>

<gadget id="calculator">5 * 0.5</gadget>
<output>2.5</output>

<gadget id="calculator">8.5 - 2.5</gadget>
<output>6</output>

<gadget id="calculator">6 / 3</gadget>
<output>2</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">8 + 20</gadget>
<output>28</output>

<result>28</result>