Answer:
19 minutes
Step-by-step explanation:
Let x be the number of minutes the call lasts.
The first three minutes of a call cost $2.00.
Then [tex]x-3[/tex] minutes left.
Each additional minute or portion of a minute of that call costs $0.50, so [tex]x-3[/tex] minutes cost [tex]\$0.50(x-3).[/tex]
The total cost is
[tex]\$2+\$0.50(x-3)[/tex]
The price of the call is $10.00, so the maximum number of minutes one can call long distance for $10.00 can be calculated from the inequality
[tex]2+0.50(x-3)\le 10\\ \\20+5(x-3)\le 100\ [\text{Multiplied by 10}]\\ \\20+5x-15\le 100\\ \\5x+5\le 100\\ \\5x\le 100-5\\ \\5x\le 95\\ \\x\le 19[/tex]
When x=19, the cost of the call is $10.00. When x<19, then the price of the call is less than $10.00.
