For this case, the first thing we must do is define a variable.
We have then:
t: number of texts
We now write the expression for each plan:
National cell:
[tex]0.15t + 5
[/tex]
World wireless:
[tex]0.19t
[/tex]
The inequality for which World wireless is cheaper than national cell is:
[tex]0.19t \ \textless \ 0.15t + 5
[/tex]
Solving for t we have:
[tex]0.19t - 0.15t \ \textless \ 5
[/tex]
[tex]0.04t \ \textless \ 5
[/tex]
[tex]t \ \textless \ 5 / 0.04
[/tex]
[tex]t \ \textless \ 125
[/tex]
Answer:
An inequality and solution that represent the number of texts for which world wireless is cheaper then national cell is:
[tex]0.19t \ \textless \ 0.15t + 5
[/tex]
[tex]t \ \textless \ 125[/tex]
