Answer:
[tex]718\ min[/tex]
Step-by-step explanation:
Let
x ----> the number of minutes
y ----> the total charge in dollars
we know that
For x>700 min
[tex]y=0.45x+40[/tex]
so
For y=48.10
substitute
[tex]48.10=0.45x+40[/tex]
Multiply by 100 both sides
[tex]4,810=45x+4,000[/tex] ----> equation without decimals
solve for x
[tex]45x=4,810-4,000\\45x=810\\x=18\ min[/tex]
To find out the total minutes we need to sum
[tex]18\ min+700\ min=718\ min[/tex]