Answer:
175 minutes
$43.75
Step-by-step explanation:
Let y = total cost
x = minutes
Plan A charges $0.17 per minute, so we multiply x by 0.17 like this: 0.17x
$14 is also already added on
y = 0.17x + 14
Plan B charges $0.13 per minute, so we multiply x by 0.13 like this: 0.13x
$21 is already added on
y = 0.13x + 21
Now we have to find where both x'es in both equations are the same
0.17x + 14 = 0.13x + 21
First, subtract 14 from both sides
0.17x + 14 = 0.13x + 21
- 14 - 14
0.17x = 0.13x + 7
Then subtract 0.13x from both sides
0.17x = 0.13x + 7
-0.13x -0.13x
0.04x = 7
Finally, divide both sides by 0.04
0.04x/0.04 = 7/0.04
x = 175
175 minutes of phone calls will need to be made on both plans for their costs to equal.
To find the price of those plans, we need to plug in the new x in one of the starting equations. We'll use the equation from Plan A.
y = 0.17(175) + 14
y = 29.75 + 14
y = 43.75
If both costs of the plans were to equal, they would cost $43.75
