yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Finding percentages with a double number line


2m read
·Nov 10, 2024

We're told that Omar's class has 28 students in it. 21 of them take the bus to school. What percentage of the students in Omar's class take the bus to school? Pause this video and see if you can figure that out.

All right, well, I'm going to try to visualize this with what we call a dub and a double number line. So let's say that is 0, and 28 is the total number of students in this classroom right over here. It's a double number line because I'm going to make another number line right below it, but I'm going to write these points in terms of percentages. So 0 students would be 0 of the students in Omar's class, and 28 students would be 100 of the students in Omar's class.

And so what we really need to do now is we know that 21 of them take the bus. 21 is going to be roughly around here, so that's 21. So we really just need to figure out: what percentage is this going to be? One way to think about it is: what fraction is 21 of 28? Well, if I write 21 over 28, we know that we can divide both the numerator and the denominator by 7. They're both divisible by 7. 21 divided by 7 is 3, and 28 divided by 7 is 4. So 21 is 3/4 of 28.

So let's divide this number line from 0 to 28 into fourths. So that would be halfway, and now we have it divided into fourths. We can see that 21 is one, two, three of these fourths. Well, if 21 is three-fourths of the way to 28, then whatever percentage this is here, that would be three-fourths of the way to a hundred.

So let's divide this into fourths as well. Now we know that one-fourth of a hundred is twenty-five percent, two-fourths of a hundred is fifty percent, and three-fourths of a hundred is seventy-five percent. So what percentage of the students in Omar's class take the bus to school? 75 percent.

More Articles

View All
Surrounded By Monkeys: What This Photographer Loves About His Job | National Geographic
I’ve been studying gelat monkeys on and off for eight years now, and I’ve seen some incredible things. Whether it’s the live birth of a gelat infant from just a few meters away, to um some intense fights where I’m just kind of stuck in the middle and gela…
Housing Expert: “Why Home Prices Will Crash In 2026”
What’s up you guys, it’s Graham here, and we got to talk about what’s happening with housing prices. Because despite record high values, constant increases, and the worst affordability in 40 years, there’s actually some good news in that a few major housi…
Finding inverse functions: rational | Mathematics III | High School Math | Khan Academy
[Voiceover] So we’re told that g of x is equal to two x minus one over x plus three. Based on this, pause the video and see if you can figure out what the inverse of g is. g inverse of x. What is that going to be equal to? Alright, I’m assuming you’ve had…
How Epicurus Keeps Calm
The ancient Greek philosopher Epicurus may seem an unlikely figure to teach us how to achieve a calm mind because of his reputation as an indulgent pleasure-seeker. Unfortunately, the teachings of Epicurus are gravely misunderstood by many. While it’s tru…
Phishing attacks | Internet safety | Khan Academy
Let’s say you get an email like this where it looks like it is from PayPal. It says “response required” really big, so this is a little bit scary. It says, “Dear you, we emailed you a little while ago to ask you for your help resolving an issue with your …
Analyzing related rates problems: expressions | AP Calculus AB | Khan Academy
The base ( b ) of the triangle is decreasing at a rate of 13 meters per hour, and the height ( h ) of the triangle is increasing at a rate of 6 meters per hour. At a certain instant ( t_0 ), the base is 5 meters and the height is 1 meter. What is the rat…