How to make Tips Calculator using Python | Python Beginner Task

Hi,
Today my teacher give me a simple task.
So i am going to solve it
Task:
When you go out to eat , you always tip 20% of the bill amount . But who's got the time to calculate the right tip amount every time ? Not you that's for sure ! You're making a program to calculate tips and save some time . Sample Output 10.0 Your program needs to take the bill amount as input and output the tip as a float .

Sample input: 50
Sample output: 10.0

if you didn't understand the code please let me know in the comment section.