On a hot day, students are lining up to buy ice cream. Let L be the number of people in line. Write a differential equation for L using the following assumptions:

Students join the line at a rate proportional to the number of people already in line, with a proportionality constant of 0.1.

Students get ice cream and leave the line at a constant rate of 0.4 people per minute.

Students get tired of standing in line and leave at a per capita rate proportional to the number of people in line, with a proportionality constant of 0.02.

L= ______________