Answer:
The piecewise function is:

Step-by-step explanation:
A piecewise function is a function that is defined in multiple intervals.
In the first interval:

The problem states that a taxi company charges $4.00 for the first mile (or part of a mile).
x is the number of miles. So
If
.
Second interval:

Here, the cost is defined by a linear function in the following format:

In which
is the initial price and r is the price paid per mile.
The problem states that each succeeding tenth of a mile costs 80 cents. So
we have the following rule of three.
1 mile - r dollars
0.1miles - 0.8 dollars



So, we have

Piecewise function:
The piecewise function is:
