Question

Sarah is hiking. She starts at 80 feet and hikes up at a constant rate of 4 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.

80+4x>270

Good work!

You just wrote an inequality to represent the situation. Now solve the associated equation, 80 + 4x = 270, to find the boundary for the inequality. Show your work or solve on paper.

80 + 4x > 270

80+4x

=

270

 

x

=

47.5

Nice!

Now figure out if the boundary, x = 47.5, is a solution to the inequality. Does x = 47.5 make the inequality true or false?

80 + 4x > 270

True

False

Answers

GPT-4o mini
To determine if the boundary \( x = 47.5 \) is a solution to the inequality \( 80 + 4x > 270 \), we substitute \( x \) with \( 47.5 \) in the inequality:

\[
80 + 4(47.5) > 270
\]

Calculating \( 4(47.5) \):

\[
80 + 190 > 270
\]

Now simplify the left side:

\[
270 > 270
\]

This statement is **false** because \( 270 \) is not greater than \( 270 \); they are equal. Therefore, the boundary \( x = 47.5 \) does not satisfy the inequality \( 80 + 4x > 270 \).

So, the answer is:

**False**.