AT&T used to have a billing scheme for long distance phone calls (Old school phones attached to your house... Don't judge me, I know I'm old because I actually remember these commercials.) that fit the following process:

When an "out of area" or "long distance" call was completed the call would be charged to your bill based on the following scheme:

-If the call was less than 20 minutes then they would charge 5 cents per minute, thus the bill was ($0.05)m,

-but if the call was 20 minutes or more then they would charge 8 cents per minute, thus the bill was ($0.08)m.

The domain of the function is the minutes used in a call:m(0,)

m(0,).

The discontinuity occurs whenm= 20.

It is non-removable because the limit from the left and right using the two calculations is different.