Math Problem Statement

Mia had $40. Then she started to receive $5 a week as an allowance. She plans to save all of her money for a bicycle and draws a graph of her planned savings. Mia lets x represent the number of weeks she has received her allowance, and y represent her total amount of money. Which of the following ordered pairs is on Mia's graph?

Solution

The problem involves Mia's allowance and her savings over time. Let's break it down step by step.

Problem:

  • Mia starts with $40.
  • Each week, she receives $5 as an allowance, which she plans to save.
  • We need to find which of the given ordered pairs (x,y)(x, y) is on Mia's graph, where:
    • xx represents the number of weeks.
    • yy represents the total amount of money Mia has.

Equation Setup:

Since Mia's savings increase by $5 every week, this is a linear equation problem. The general form of a linear equation is: y=mx+by = mx + b where:

  • mm is the rate of change (slope, which is $5 per week),
  • bb is the starting amount (initial money, which is $40).

Thus, the equation for Mia's total savings is: y=5x+40y = 5x + 40

Checking the Ordered Pairs:

Let's plug in the xx-values from the given ordered pairs and see if the corresponding yy-values match the equation.

  1. (6,30)(6, 30): y=5(6)+40=30+40=70(not 30)y = 5(6) + 40 = 30 + 40 = 70 \quad (\text{not } 30) This is not on the graph.

  2. (2,80)(2, 80): y=5(2)+40=10+40=50(not 80)y = 5(2) + 40 = 10 + 40 = 50 \quad (\text{not } 80) This is not on the graph.

  3. (1,40)(1, 40): y=5(1)+40=5+40=45(not 40)y = 5(1) + 40 = 5 + 40 = 45 \quad (\text{not } 40) This is not on the graph.

  4. (4,60)(4, 60): y=5(4)+40=20+40=60(correct)y = 5(4) + 40 = 20 + 40 = 60 \quad (\text{correct}) This is on the graph.

Conclusion:

The correct ordered pair that is on Mia's graph is (4, 60).

Let me know if you need further details or if you'd like clarification on anything!

Related Questions:

  1. How can you determine the slope from a linear equation?
  2. What is the significance of the y-intercept in real-life scenarios like this?
  3. How would the graph look if Mia saved $10 per week instead of $5?
  4. How do you graph the line of an equation like y=5x+40y = 5x + 40?
  5. How would the equation change if Mia started with $0 instead of $40?

Tip:

In problems involving constant savings or spending over time, always look for a linear relationship where the slope represents the rate of change.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Algebra

Formulas

y = mx + b

Theorems

Linear equation theory

Suitable Grade Level

Grades 6-8