Assume that ten people each hold a pail and go to the faucet to draw water at the same time. It takes 1 minute for the faucet to fill the bucket of the first person, and 2 minutes to fill the bucket of the second person.  … Going on like this, when there are only two faucets, cleverly arrange these ten people to fetch water so that their total time-consuming is the least. How many minutes is this time.
设有十个人各拿着一只提桶同时到水龙头前打水，设水龙头注满第一个人的桶需要1分钟，注满第二个人的桶需要2分钟，…．如此下去，当只有两个水龙头时，巧妙安排这十个人打水，使他们总的费时时间最少．这时间等于多少分钟．
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<gadget id="calculator">5 + 6</gadget>
<output>11</output>

<gadget id="calculator">11 * 3</gadget>
<output>33</output>

<gadget id="calculator">7 + 8</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

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

<gadget id="calculator">19 * 1</gadget>
<output>19</output>

<gadget id="calculator">15 + 28 + 33 + 30 + 19</gadget>
<output>125</output>

<result>125</result>