Ratio problem with basic algebra | Linear equations and inequalities | Algebra Basics | Khan Academy

TL;DR

The video teaches how to solve a ratio problem by adding girls to a classroom to change the boy to girl ratio.

Transcript

Now that have a basic understanding of what a ratio is, let's see if we can tackle some more advanced problems. So, I have a classroom. It's got 55 students in it. 55 students. And I also know that the ratio of boys to girls, the ratio of I'll write it this way, boys to girls is 4:7. What I want to know is, how many girls do I need to add. So, how ... Read More

Key Insights

• 👨‍👩‍👧‍👦 Ratios can be used to represent the relationship between different quantities, such as the number of boys to girls in a classroom.
• 👥 The total number of students in the classroom helps determine the number of groups when dividing them into equal-sized groups based on the given ratio.
• 🥳 Solving ratio problems often involve cross-multiplication or finding equivalent ratios to determine the unknown quantity.

Questions & Answers

Q: What is the current boy to girl ratio in the classroom?

The current boy to girl ratio in the classroom is 4:7, meaning there are 4 boys for every 7 girls.

Q: How many boys and girls are currently in the classroom?

There are currently 20 boys and 35 girls in the classroom, making a total of 55 students.

Q: How many girls need to be added to change the ratio to 1:2?

To change the ratio to 1:2, 5 more girls need to be added to the classroom.

Q: What is the new boy to girl ratio after adding the girls?

After adding the 5 girls, the new ratio becomes 20 boys to 40 girls, which is equivalent to a ratio of 1:2.

Summary & Key Takeaways

• The classroom currently has 55 students with a boy to girl ratio of 4:7.

• To change the ratio to 1:2, 5 girls need to be added to the classroom.

• After adding the girls, the new ratio is 20 boys to 40 girls.