$\"\"$

Dale has a maximum of $\"\"$ minutes on his cell phone plan.

Let $\"\"$ be the number of day time minutes.

Let $\"\"$ be the number of night time minutes.

The inequality is $\"\"$ . Dale plans to use at least twice as many daytime minutes as night time minutes.

The inequality is $\"\"$ .

If Dale uses atleast $\"\"$ night time minutes and does not go over his limit.

The inequality is $\"\"$ .

Day time minutes cost $\"\"$ , and night time minutes cost $\"\"$ .

The function is $\"\"$ .

$\"\"$

Find the his maximum and minimum bill.

Write a system of inequality.

$\"\"$

The function is $\"\"$ .

Graph:

Graph the inequalities are $\"\"$ and $\"\"$ .

$\"\"$

Observe graph:

The coordinate points are $\"\"$ , $\"\"$ and $\"\"$ .

$\"\"$

Make a table:

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

Therefore, the maximum bill is $\"\"$ and minimum bill is $\"\"$ .

$\"\"$

His maximum bill is $\"\"$ and minimum bill is $\"\"$ .