Question

A phone company offers two monthly plans. Plan A costs $12 plus an additional $0.16 for each minute of calls. Plan B costs $29 plus an additional $0.12 for

each minute of calls.

For what amount of calling do the two plans cost the same?

What is the cost when the two plans cost the same?

Answer 1

If we put on equations

• y=0.16x+12
• y=0.12x+29

Amount of calling is x and cost is y

solve

• 0.16x+12=0.12x+29
• 0.04x=17
• x=17/0.04
• x=425min

Cost

• 0.12(425)+29=$80

Answer 2

• 425 min
• $80

Explanation:

The equation to reflect the monthly plans:

• Plan A f(x) = 0.16x + 12
• Plan B g(x) = 0.12x + 29

We need to find the value of x when f(x) = g(x):

• 0.16x + 12 = 0.12x + 29
• 0.16x - 0.12x = 29 - 12
• 0.04x = 17
• x = 17/0.04
• x = 425 minutes

The cost is:

• $0.16*425 + $12 = $80