Given:
[tex]PlanA=0.16\text{ for each minutes of calls}[/tex][tex]PlanB=25\text{ monthly fee plus 0.12 for each minute of calls}[/tex]
To Determine: The numbers of calls for the which the two plans are equal
Solution
Let x be the number of minutes of calls for which the two plans are equal
The cost of plan A is
[tex]C_{ost\text{ of plan A}}=0.16x[/tex]
The cost of plan B
[tex]C_{ost\text{ of plan B}}=25+0.12x[/tex]
If the cost for the two plans are equal, then
[tex]0.16x=25+0.12x[/tex]
Solve for x
[tex]\begin{gathered} 0.16x-0.12x=25 \\ 0.04x=25 \\ x=\frac{25}{0.04} \\ x=625 \end{gathered}[/tex]
Hence, the number of minutes of calls for which two plans are equal is 625 minutes
