4.2.5 Practice - Algebra 1 | OpenStax

Skip to Content Go to accessibility page

4.2.5 Practice

4.2.5 • Practice

Complete the following questions to practice the skills you have learned in this lesson.

The height of water in a bathtub, $w$ , is a function of time, $t$ . Let $P$ represent this function. Height is measured in inches and time in minutes.

What does each equation mean in this situation?

$P(0) = 0$

The height of the water is 10 inches after 4 minutes.
After 10 minutes, the height of the water is 4 inches.
The bathtub starts out with no water.
After 20 minutes, the bathtub is empty.

$P(4) = 10$

The height of the water is 10 inches after 4 minutes.
After 10 minutes, the height of the water is 4 inches.
The bathtub starts out with no water.
After 20 minutes, the bathtub is empty.

$P(10) = 4$

The height of the water is 10 inches after 4 minutes.
After 10 minutes, the height of the water is 4 inches.
The bathtub starts out with no water.
After 20 minutes, the bathtub is empty.

$P(20) = 0$

The height of the water is 10 inches after 4 minutes.
After 10 minutes, the height of the water is 4 inches.
The bathtub starts out with no water.
After 20 minutes, the bathtub is empty.

Function $C$ takes time for its input and gives a student’s Monday class for its output.

Use function notation to represent: A student has English at 10:00.

$C$ (10:00)=Monday
$C$ (Monday)=English at 10:00
$C$ (10:00)=English
$C$ (English)=10:00

Function $f$ gives the distance of a dog from a post, in feet, as a function of time, in seconds, since its owner left.

Find the value of $f(20)$ .

3.5
3.4
3.3
3.2
3.1
3.0

Find the value of $f(140)$ .

3.5
3.4
3.3
3.2
3.1
3.0

Looking at the graph below, what does the point $(1980, 83)$ mean?

There were 83 million more people in 1980 than 1979.
In 1980, the world population increased by 83 million people.

Function $R$ gives the number of inches of rain after $h$ hours. What does the statement $R(6)=5$ mean?

After 6 hours, there was 5 inches of rain.
After 5 hours, there was 6 inches of rain.
At 6 hours, the rate is 5 inches per hour of rain.

Function $R$ gives the number of inches, $T$ , of rain after $h$ , hours. Choose which function notation represents this situation.

$T=R(h)$
$h=T(R)$
$h=R(T)$
$R=T(h)$

Use function notation to represent that the number of miles, $m$ , a car travels as a function of time, $t$ .

$t=f(m)$
$t=m(f)$
$m=f(t)$
$f=m(t)$

Order a print copy

Citation/Attribution

Reuse and redistribution of this content in digital or print format:

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
This book uses the Creative Commons Attribution-NonCommercial-ShareAlike License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute OpenStax, and must distribute any derivative works under the same license.
Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.

Attribution information

If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:
Access for free at https://openstax.org/books/algebra-1/pages/about-this-course
If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:
Access for free at https://openstax.org/books/algebra-1/pages/about-this-course

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

Authors: Lynn Marecek, MaryAnne Anthony-Smith, Andrea Honeycutt Mathis, Jay Abramson, Sharon North, Amy Baldwin, Alyssa Howell
Publisher/website: OpenStax
Book title: Algebra 1
Publication date: Jun 4, 2025
Location: Houston, Texas
Book URL: https://openstax.org/books/algebra-1/pages/about-this-course
Section URL: https://openstax.org/books/algebra-1/pages/4-2-5-practice

© Apr 23, 2026 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.