Shaniece took a taxi from her house to the airport. The taxi company charged a pick-up fee of $3.40 plus $3.50 per mile. The total fare was $80.40, not including the tip. Write and solve an equation which can be used to determine xx, the number of miles in the taxi ride.

To find the number of miles \( x \) that Shaniece traveled in the taxi, we can set up the equation based on the information given about the taxi fare.

The total fare consists of a pick-up fee plus a charge per mile. The pick-up fee is $3.40, and the charge is $3.50 per mile. According to the problem, the total fare was $80.40.

We can write the equation for the total fare as:

\[ \text{Total fare} = \text{Pick-up fee} + (\text{Cost per mile} \times \text{Number of miles}) \]

Plugging in the values, we have:

\[ 80.40 = 3.40 + 3.50x \]

Now, we will solve for \( x \).

1. Subtract the pick-up fee from both sides:

\[ 80.40 - 3.40 = 3.50x \]

\[ 77.00 = 3.50x \]

2. Now, divide both sides by 3.50 to isolate \( x \):

\[ x = \frac{77.00}{3.50} \]

3. Performing the division gives:

\[ x = 22 \]

Thus, the number of miles in the taxi ride is \( \boxed{22} \).