Adult tickets for the museum are 5 yuan each, and two adults can bring a child for free; children's tickets are 4 yuan each; buy a group of 5 joint tickets, an average of 3.8 yuan each, kindergarten teacher Zhang led 4 children to visit, I met Mr. Wang and Mr. Li. They each brought 5 children. How can I buy a ticket with the least amount of money? How much is the least amount?
博物馆成人票每张5元，两名成人可免费带一名儿童；儿童票每张4元；买5人一组的联票，平均每张3.8元，幼儿园张老师带领4个小朋友来参观，遇见王老师和李老师，他们分别带了5个小朋友，怎样买票花钱最少，最少要花多少钱？
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">3.8 * 10</gadget>
<output>38</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">10 + 38 + 16</gadget>
<output>64</output>

<result>64</result>