Question

One smartphone plan costs $30 per month for talk and messaging and $8 per gigabyte of data used each

month. A second smartphone plan costs $60 per month for talk and messaging and $3 per gigabyte of
data used each month. Let c represent the total cost in dollars and d represent the amount of data used in
[c= 30 + 8d
gigabytes. The system of equations
can be used to represent this situation. How many
c=60 + 3d
gigabytes would have to be used for the plans to cost the same? What would that cost be?

Answer 1

A;

30 + 8g = c

B;

60 + 3g = c

60 + 3g = 30 + 8 g

30 = 5g

g = 6

6 gigs would have to be used in both for the cost to be the same