In a competition, the pass rate of a certain class is 50%. If you want to improve the score of 4 students from 59.5 to 60, the pass rate is 60%. How many students are there in this class?
在一次竞赛中，某班的及格率为50%，如要把4名同学的成绩由59.5分提高到60分，及格率为60%，该班共有多少名学生？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">(3/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">4 / (1/10)</gadget>
<output>40</output>

<result>40</result>