Teacher Wang took 8 students to paint in Baishan Park. The ticket office said: 5 yuan per ticket, 4 yuan per ticket if you buy more than 10 tickets. What is the minimum cost for Mr. Wang to buy a ticket from the ticket office?
王老师带8个学生去白山公园画画，售票处写着：门票每张5元，购10张以上每张4元．王老师从售票处购票最少要用多少元钱？
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>