Gr10 Math
posted by Ana .
Charlene is looking into cell phone plans.
Cell plus gives unlimited minutes for $50/month.A1 Cell offers a $40 monthly fee, plus 5¢/min for any time over 300min oer month.
a)Define two variables and write a linear equation to represent the charges for each company.
b)Which plan should Charlene choose if she estimates that she will use her phone 10h per month? 6h per month?

cost+ = 50
costA1= 40 + .05(Time300)
Lets find when the costs are the same: set them equal.
50=40+.05(T300)
10*20=T300
T=500 min they are equal. So at 6hrs, 3600 min, the A1 is cheaper, at 10hr (600 min, the cost+ is cheaper).
Your teacher is too easy. 
We aren't supposed to solve the system so it confused me, but thank you for the answers.