a parking lot. It costs five yuan to park each time. Add two yuan per hour, Dad paid a total of 12.7 yuan, how many hours did he stop?
一个停车场．每次停车要五元．每一小时增加二元，爸爸一共付了12.7元，他停了几个小时？
<gadget id="calculator">12.7 - 5</gadget>
<output>7.7</output>

<gadget id="calculator">7.7 / 2</gadget>
<output>3.85</output>

<gadget id="calculator">3.85 + 1</gadget>
<output>4.85</output>

<result>4.85</result>