To determine which expression represents the cost of Roxy's bill last month before any taxes or additional fees, let's carefully analyze the charges:
1. Monthly Base Charge: The cell phone company charges a fixed amount of [tex]$40 per month for unlimited calling. This cost is constant and does not vary with the number of text messages sent.
2. Text Message Charge: Additionally, the company charges $[/tex]0.20 per text message sent. If [tex]\( t \)[/tex] represents the number of text messages Roxy sent, then the total cost for the text messages would be [tex]\( 0.2 \times t \)[/tex] dollars.
To find the total cost of Roxy's bill, we need to combine both of these charges:
- The fixed monthly charge of $40.
- The variable charge based on the number of text messages.
Thus, the total cost [tex]\( C \)[/tex] is given by the sum of these two components:
[tex]\[ C = 40 \text{ (fixed monthly charge)} + 0.2t \text{ (cost for text messages)} \][/tex]
Therefore, the correct expression representing the cost of her bill last month before any taxes or additional fees is:
[tex]\[ 40 + 0.2t \][/tex]
From the given options, we can see that the correct expression is:
[tex]\[ \boxed{40 + 0.2 t} \][/tex]
This correctly combines the fixed charge and the variable charge for the text messages.
