Three 12-meter-long round copper bars and five 9-meter-long round steel bars are sawn into 3-meter-long pieces. It takes an average of 5 minutes to cut each piece. How many minutes are needed to saw all of them?
把3根12米长的圆铜条和5根9米长的圆钢条都锯成3米长的小段，每锯断一段平均需要5分钟，全部锯完共需要多少分钟？
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">9 + 10</gadget>
<output>19</output>

<gadget id="calculator">19 * 5</gadget>
<output>95</output>

<result>95</result>