A ratio is a simplified comparison between two or more components. For example, if a person A, and a person B is going to start a business. They don’t know how much money they are going to make. In this case they decide on ratio how they will share the profit. 5:5 would be sharing the profit equally. 6:4 means if they make $10 profit, A will get $6 and B will get $4.
However, in questions, they normal do not give ratio in whole numbers. The key concept of ratio is that you can multiply or divide same number on both side, just like equations.
For example,
1:2 = 2:4 = 3: 6 = 4: 8
You can multiply or divide same number on both sides like this. So when the ratio is given not whole number, you need to multiply a number to make them into whole number. For example,
1.5 : 2.5
This is not a whole number. To make this into whole number ratio, let’s multiply 2 on both side.
3:5
The ratio was actually 3:5 which is much simpler to see.
Also, there are questions like A = 3C and B = 2C. Find ratio between A to B.
For this question, you need to write it out. The question asks for A:B
In the question A = 3C, and B = 2C
Therefore A:B = 3C : 2C
We can multiply or divide same number on both side, so if we divide by C on both side we get
3:2
Therefore the ratio between A and B is 3:2.
Another example would be 2A = 3C, 4B = 5C, Find ratio A to B
For this question, you need to express A and b in terms of C
A = 3C / 2 and B = 5C / 4 we divided each equation with coefficient of A and B.
Then A: B = 3C/2 : 5C/4
Let’s multiply both side by 4 then
6C:5C
Let’s divide by C on both side then
6:5
Therefore ratio of A:B = 6:5
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This article was written for you by Troy, one of the tutors with Test Prep Academy.