Question

ChitChat wireless charges $0.30 per minute plus a monthly base fee. In september, Maggie used 120 minutes and her bill was $50. Write and solve an equation to find the cost if Maggie uses 165 minutes in october

Answer 1

Let $k =  the monthly base fee.
The variable cost is $0.30 per minute.

Let
C = total cost in a month
x = minutes used

September:
x = 120 minutes
C = $50
Therefore
k + (0.30)(120) = 50
k + 36 = 50
k = $14

October:
x = 165 minutes
The cost is
C = 14 + (0.3)(165) 
C = $63.5

Answer: $63.50