Class A has 60 students and Class B has 80 students. How many people are transferred from class A to class B so that the ratio of the number of people in class A and class B is 2:3?
甲班有60人，乙班有80人．从甲班调几人到乙班才能使甲、乙两班人数的比是2：3？
<gadget id="calculator">60 + 80</gadget>
<output>140</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">140 * (2/5)</gadget>
<output>56</output>

<gadget id="calculator">60 - 56</gadget>
<output>4</output>

<result>4</result>