Question

Ms. Jones is hiking. She starts at 40 feet and hikes up at a constant rate of 8 feet per minute. How many minutes could she be hiking if she is above 270 feet in elevation?

Write an inequality to represent the situation. Use x to represent the number of minutes.

40+8x>270

Excellent!

You just wrote an inequality to represent the situation. Now solve the associated equation, 40 + 8x = 270, to find the boundary for the inequality. Show your work or solve on paper.

40 + 8x > 270

40+8x

=

270

 

x

=

28.75

Excellent!

Now figure out if the boundary, x = 28.75, is a solution to the inequality. Does x = 28.75 make the inequality true or false?

40 + 8x > 270

True

False

You got it!

You found that x= 28.75 makes the inequality false. Now test x= 28 and x= 29. Do they make the inequality true or false?

x= 28x=28.75 (boundary)x= 2940 + 8x > 270

False

True

False

False

True

True

False

Good work!

Use the table to help you write the solution to the inequality.

x= 28x=28.75 (boundary)x= 2940 + 8x > 270FalseFalseTrue



 



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Answers

GPT-4o mini
To summarize the work and complete the table, let’s go through the findings step-by-step and clarify the solution to the inequality.

### Step 1: Write the Inequality
The situation is represented by the inequality:
\[
40 + 8x > 270
\]

### Step 2: Solve the Associated Equation
To find the boundary:
\[
40 + 8x = 270
\]
Subtract 40 from both sides:
\[
8x = 230
\]
Divide by 8:
\[
x = 28.75
\]

### Step 3: Check if the Boundary is a Solution
Now, we will check if \( x = 28.75 \) makes the inequality true:
\[
40 + 8(28.75) = 40 + 230 = 270
\]
The inequality is \( 270 > 270 \), which is false. Thus, \( x = 28.75 \) is not a solution to the inequality.

### Step 4: Test values
- **Test \( x = 28 \)**:
\[
40 + 8(28) = 40 + 224 = 264
\]
Check: \( 264 > 270 \) → **False**

- **Test \( x = 29 \)**:
\[
40 + 8(29) = 40 + 232 = 272
\]
Check: \( 272 > 270 \) → **True**

### Step 5: Construct the Solution
Based on the values:
- For \( x = 28 \) (false) and \( x = 29 \) (true), the solution to the inequality \( 40 + 8x > 270 \) is \( x > 28.75 \).

### Final Solution
The final expression for the solution can be represented as:
\[
x > 28.75
\]

### Completing the Table
Using the findings, we can fill the table like this:

| x | 28 | 28.75 (boundary) | 29 |
|---------|-------|-------------------|---------|
| \( 40 + 8x > 270 \) | False | False | True |

### Solution Representation
From the tests, the complete solution to the inequality is:
\[ x > 28.75 \]

Therefore, Ms. Jones can hike for more than 28.75 minutes in order to be above 270 feet in elevation.