During the autumn outing, the students in class one rented a few cruise ships. If there are 4 people in each boat, one of them cannot fit. If there are 5 people in each boat, 2 boats can be rented less, and each person can pay 0.4 yuan less for the boat per hour. How much is the hourly rental fee for each boat?
秋游的时候，一班的同学租了几只游船．如果每只船坐4人，有一个人坐不下．如果每只船坐5人，就可以少租2只船，而每人每小时可以少付船费0.4元．每只船每小时租费是多少元？
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">1 + 10</gadget>
<output>11</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">11 / 1</gadget>
<output>11</output>

<gadget id="calculator">11 * 4</gadget>
<output>44</output>

<gadget id="calculator">44 + 1</gadget>
<output>45</output>

<gadget id="calculator">0.4 / 2</gadget>
<output>0.2</output>

<gadget id="calculator">45 * 0.2</gadget>
<output>9</output>

<result>9</result>