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GCSE Ratio and Proportion

Best Buys

Learn best buys as part of use multiplicative reasoning in ratio, proportion, scaling, rates, similarity and real-life graph contexts.

Key idea

Find the multiplier or unit amount, then apply the same proportional change to the value you need.

What you will learn

Use best buys meaning confidently.
Use best buys representations confidently.
Use best buys methods confidently.
Use best buys applications confidently.

Success checklist

I can explain what best buys means.
I can choose a suitable method without being told.
I can show clear working and check my answer.

Worked example

Share £40 in the ratio 3:5.

Model method

Step 1

There are 3 + 5 = 8 parts.

Step 2

Each part is £40 ÷ 8 = £5.

Step 3

The shares are 3 × £5 and 5 × £5.

Answer

£15 and £25

Quick practice

Question 1

Share £60 in the ratio 2:3.

Question 2

5 pens cost £3. Find the cost of 12 pens.

Question 3

Increase £80 by 15%.

Related resources

These are linked to the wider Ratio and Proportion topic for now.

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