Math Problem Statement

Whenever Judy goes for a run, she does her best to maintain the same pace. No matter how far she runs, she always stretches for the same amount of time. The table shows the distance Judy covered on some recent runs and the total number of minutes she spent exercising, including the time she spent stretching. Miles run (d) Exercise time in minutes (T) 2 33 4 51 5 60 7 78 Complete the equation for the function relating the total time Judy spends exercising in minutes, T, to the distance she runs in miles. T= d+ Complete the sentences to make true statements.

Solution

To complete the equation and sentences, we need to determine the relationship between the total exercise time TT and the distance Judy runs dd. Here's how:


Step 1: Identify the relationship

The total exercise time TT includes:

  1. A constant stretching time (denoted as SS).
  2. A running time that depends on her pace (minutes per mile).

Step 2: Determine Judy's pace (rate of running)

The table shows that the additional time Judy spends running as the distance increases is consistent. For example:

  • Between 2 and 4 miles: 5133=1851 - 33 = 18 minutes for 2 miles → Pace: 182=9\frac{18}{2} = 9 minutes per mile.
  • Between 4 and 7 miles: 7851=2778 - 51 = 27 minutes for 3 miles → Pace: 273=9\frac{27}{3} = 9 minutes per mile.

Thus, her running pace is 9 minutes per mile.


Step 3: Determine the stretching time (SS)

From the table, subtract the running time for any distance to find the constant stretching time:

  • At d=2d = 2: Total time T=33T = 33, Running time 2×9=182 \times 9 = 18, so S=3318=15S = 33 - 18 = 15.
  • At d=4d = 4: Total time T=51T = 51, Running time 4×9=364 \times 9 = 36, so S=5136=15S = 51 - 36 = 15.

Thus, the stretching time is 15 minutes.


Step 4: Write the equation

The total exercise time TT in minutes is the sum of the stretching time SS and the running time (9d9d, where dd is the distance in miles):

T=9d+15T = 9d + 15


Step 5: Complete the sentences

  1. Judy spends 9 minutes per mile running.
  2. She spends 15 minutes stretching, no matter how far she runs.

Final Answer

The equation is:

T=9d+15T = 9d + 15

Would you like a detailed explanation of how to solve similar problems or additional examples? 😊


Related Questions

  1. How would the equation change if Judy’s stretching time increased to 20 minutes?
  2. What is Judy’s total exercise time if she runs 10 miles?
  3. How far did Judy run if her total exercise time was 69 minutes?
  4. What does the slope of the equation T=9d+15T = 9d + 15 represent in this context?
  5. How would the graph of T=9d+15T = 9d + 15 look, and what does the y-intercept represent?

Tip

When analyzing linear relationships in word problems, identify fixed (constant) values and rates of change to build the equation systematically.

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Math Problem Analysis

Mathematical Concepts

Linear Relationships
Algebra
Rates and Constants

Formulas

T = md + b (linear equation)

Theorems

Slope-Intercept Form

Suitable Grade Level

Grades 6-8