Question

The scatterplot below shows the cost of phone calls Marcy made to her sister overseas in relationship to the number of minutes per phone call.

based on this graph, what is the approximate cost of a 65-minute phone call overseas?

★ $16

★ $18

★ $20

★ $24

Answer 1

I believe the answer is 18

Answer 2

m = (15 - 5)/(45 - 10) = 10/35 = 2/7

15 = (2/7)(45) + b

105/7 = 90/7 + b

b = 15/7

f(x) = (2/7)x + (15/7)

f(65) = (2/7)(65) + (15/7) = 145/7 = $20.71

The closest answer to this approximation is C.