In the mid-term evaluation of Class 51, 5 people were rated as five good students, the number of four good boys was 20% more than the five good students, and the number of three good students was 50% more than the four good boys. How many good students are there?
五1班在期中评比中，5人被评为五好学生，四好少年的人数比五好学生多20%，三好学生比四好少年多50%．三好学生有多少人？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">5 * (6/5) * (3/2)</gadget>
<output>9</output>

<result>9</result>