Question

When making a telephone call using a calling card, a call lasting 5 minutes cost $0.95. A call lasting 13 minutes cost $1.75. Let y be the cost of making a call lasting x minutes using a calling card. Write a linear equation that models the cost of making a call lasting x minutes.

A. y = 10x - 981/20
B. y = -0.1x + 1.45
C. y = 0.1x + 0.45

Answer 1

The linear equation that models the cost of making a call lasting x minutes using a calling card is y = -0.1x + 1.45.

Step-by-step explanation:

To write a linear equation that models the cost of making a call lasting x minutes using a calling card, we can use the given information about two calls. If a 5-minute call costs $0.95 and a 13-minute call costs $1.75, we can set up two equations:

0.95 = 5m + b

1.75 = 13m + b

Solving these equations, we find that m = -0.1 and b = 1.45. Therefore, the linear equation that models the cost of making a call lasting x minutes is y = -0.1x + 1.45.