Ratio and Proportion - IELTS Academic Writing IELTS Study Notes
Overview
Have you ever tried to share a pizza fairly with your friends, or followed a recipe to bake cookies? Then you've already used **ratio and proportion** without even knowing it! These are super useful ideas that help us compare amounts and understand how things relate to each other. In the IELTS Academic Writing Task 1, you'll often see charts, graphs, or tables that show how different numbers compare. Maybe it's the number of students studying different subjects, or how much a country's population changed over time. Knowing about ratio and proportion helps you describe these comparisons clearly and accurately, making your writing much stronger. Think of it like being a detective for numbers. Ratio and proportion give you the special magnifying glass to see the connections and tell the story behind the data. It's not just about big words; it's about making sense of the world around you!
What Is This? (The Simple Version)
Imagine you have a basket of fruit. There are 3 apples and 2 bananas. If someone asks you to compare the number of apples to bananas, you could say there are '3 apples for every 2 bananas'. That's exactly what a ratio is!
A ratio is just a way to compare two or more numbers. It tells you how much of one thing there is compared to another. We often write ratios using a colon (:) like this: 3:2 (read as '3 to 2'). It's like saying, 'For every 3 apples, there are 2 bananas.'
Now, what about proportion? Imagine you have another basket, and it has 6 apples and 4 bananas. Notice anything? The relationship between apples and bananas is still the same! For every 3 apples, there are 2 bananas. When two ratios are equal, we say they are in proportion. It means they have the same 'balance' or 'relationship' even if the total numbers are different.
Think of it like scaling a recipe: if a recipe for 2 people uses 1 cup of flour and 2 eggs, a recipe for 4 people (double the amount) would use 2 cups of flour and 4 eggs. The ratio of flour to eggs (1:2) stays the same, so the recipes are in proportion.
Real-World Example
Let's say you're looking at a graph for your IELTS task, and it shows the number of people who prefer coffee versus tea in a small town.
- Year 2000: 60 people preferred coffee, and 30 people preferred tea.
- Year 2020: 100 people preferred coffee, and 50 people preferred tea.
Let's break it down:
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Find the ratio for Year 2000:
- Coffee to Tea = 60 : 30
- We can simplify this ratio by dividing both numbers by their biggest common friend (which is 30). So, 60 ÷ 30 = 2, and 30 ÷ 30 = 1.
- The simplified ratio is 2:1. This means for every 2 people who liked coffee, 1 person liked tea.
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Find the ratio for Year 2020:
- Coffee to Tea = 100 : 50
- Again, simplify by dividing both numbers by 50. So, 100 ÷ 50 = 2, and 50 ÷ 50 = 1.
- The simplified ratio is also 2:1. This means for every 2 people who liked coffee, 1 person liked tea.
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Are they in proportion?
- Yes! Since the ratio of coffee to tea is 2:1 in both years, we can say that the preference for coffee versus tea remained in proportion (or stayed the same relatively) between 2000 and 2020, even though the total number of people surveyed might have changed. You could write: "The ratio of coffee drinkers to tea drinkers remained constant at 2:1 over the two decades."
How It Works (Step by Step)
When you see numbers in your IELTS task and want to use ratios and proportions, here's how to do it: 1. **Identify the two (or more) things you want to compare.** For example, 'boys to girls' or 'spending on food to spending on housing'. 2. **Write down the numbers in the order you want to compar...
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Key Concepts
- Ratio: A comparison of two or more numbers, showing how much of one thing there is compared to another.
- Proportion: When two ratios are equal, meaning they have the same relationship or balance.
- Simplifying a ratio: Dividing both parts of a ratio by the largest number that goes into both evenly to make it easier to understand.
- Colon (:): The symbol used to write ratios, for example, 2:1.
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Exam Tips
- →Always simplify ratios to their lowest whole numbers to make your descriptions clearer and more concise.
- →Use a variety of phrases to describe ratios (e.g., 'twice as many', 'a third of', 'a ratio of 3 to 1') to show off your vocabulary.
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