🎲 Probability Explorer 11+ Edition

This lesson introduces the basics of ratios within the topic of Maths Probability. You’ll learn how ratios compare quantities and how they appear in 11+ questions. After studying the explanation, try the quiz to check your understanding. As part of 11+ Maths Probability , this page helps you build confidence and accuracy through guided practice.

Tutorial :

Ratios are a way of comparing two or more quantities. In 11+ Maths Probability, ratios often help you understand how likely an event is to happen. A ratio shows the relationship between parts, such as 2:3, meaning “for every 2 of the first item, there are 3 of the second.”

Start by simplifying ratios. Just like fractions, you can divide both numbers by the same factor.
Example: 12:18 → divide by 6 → 2:3. A simplified ratio makes problems easier to handle under exam pressure.

Ratios also help when working with probability situations.
Example: A bag has red and blue counters in the ratio 1:4. This means that out of every 5 counters, 1 is red and 4 are blue. The probability of picking a red counter is therefore 1 out of 5.

You can convert ratios into fractions when working with probabilities:
If the ratio is 3:7, then the total number of parts is 10. The probability of the first part is 3/10, and the second is 7/10.

Exam Tips:

• Always add the ratio parts to find the total number of equal sections.

• Keep ratios in simplest form to avoid mistakes.

• Read carefully: the first number in a ratio always refers to the first item mentioned.

• Draw a quick bar model if the numbers feel confusing—it helps visualise the parts clearly.

Understanding ratios is essential in many Maths Probability questions. With practice, you’ll be able to compare quantities and calculate probabilities confidently.

More Resources :

• Decimals 
• Fractions
• General Maths

External links :

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