Question

40 points. Topic: Solving a word problem using a system of linear equations of the form y = mx + b A phone company offers two monthly plans. Plan A costs $8 plus an additional $0.17 for each minute of calls. Plan B costs $21 plus an additional $0.12 for each minute of calls. For what amount of calling do the two plans cost the same? ____minutes What is the cost when the two plans cost the same? $_____

Answer 1

The plans will cost the same for $260 minutes of calling. These minutes will cost $52.20

Explanation:

Plan A: $8 + ($0.17/min)t

Plan B: $21 + ($0.12/min)t

Equate these, obtaining $8 + ($0.17/min)t = $21 + ($0.12/min)t, or:

($0.17/min)t - ($0.12/min)t = $13, or

($0.05/min)t = $13 , so t = 260 minutes. The plans will cost the same for $260 minutes of calling.

Find the cost in this situation: It is $21 + ($0.12/min)(260 min), or $52.20