Math Problem Statement
A phone company offers two monthly plans. Plan A costs
US$22
plus an additional
US$0,11
for each minute of calls. Plan B costs
US$14
plus an additional
US$0,15
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?
Solution
Let's define the number of minutes of calls as .
Plan A:
- Fixed cost: $22
- Variable cost: $0.11 per minute
The total cost for Plan A can be expressed as:
Plan B:
- Fixed cost: $14
- Variable cost: $0.15 per minute
The total cost for Plan B can be expressed as:
Finding the amount of calling where the two plans cost the same:
To find the number of minutes where both plans cost the same, we set the two cost expressions equal to each other and solve for :
Subtract 14 from both sides:
Subtract from both sides:
Solve for by dividing both sides by 0.04:
So, the two plans cost the same when you make 200 minutes of calls.
Cost when the two plans cost the same:
To find the cost, substitute into either cost equation (both should give the same result):
Using Plan A's cost equation:
So, when the two plans cost the same, the cost is $44.
Would you like more details on this solution or have any other questions? Here are some related questions to explore:
- How would the costs change if Plan B had a lower per-minute rate?
- What if Plan A had a lower fixed cost?
- How many minutes should one talk to make Plan A cheaper than Plan B?
- How do the costs differ if the number of minutes is 100?
- How would you graph the cost of both plans?
- What if a third plan was introduced with a different cost structure?
- How does a change in fixed cost affect the break-even point?
- How would rounding of costs to the nearest cent affect the results?
Tip: When comparing costs in similar scenarios, it's often useful to express both cost structures algebraically and find the intersection point for a clear comparison.
Ask a new question for Free
By Image
Drop file here or Click Here to upload
Math Problem Analysis
Mathematical Concepts
Linear equations
Cost analysis
Formulas
Equation of a line
Theorems
-
Suitable Grade Level
Grades 7-9
Related Recommendation
Comparing Two Phone Plans with Linear Equations
Finding the Break-even Point for Two Cell Phone Plans Using Linear Equations
Comparing Cell Phone Plans: Solving Linear Equations to Find Cost Break-even Point
Phone Plan Cost Analysis: Comparing Monthly Plans
Cost Comparison: When Do Two Phone Plans Become Equal?