A phone company offers two monthly plans. Plan A costs $19 plus an additional $0.12 for each minute of calls. Plan B costs $9 plus an additional $0.14 for each minute of calls.

Question

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

Let x be the number of minutes of calls.

For Plan A, the cost would be $19 + 0.12x.
For Plan B, the cost would be $9 + 0.14x.

Setting the two costs equal to each other:
19 + 0.12x = 9 + 0.14x

Subtracting 0.12x from both sides:
19 = 9 + 0.02x

Subtracting 9 from both sides:
10 = 0.02x

Dividing by 0.02 on both sides:
x = 500

Therefore, the two plans cost the same for 500 minutes of calls.

To find the cost at this point:
For Plan A: $19 + 0.12(500) = $19 + $60 = $79
For Plan B: $9 + 0.14(500) = $9 + $70 = $79

So, the cost when the two plans cost the same is $79 for 500 minutes of calls.