Ratios & Proportions
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Lesson overview
Sharing and comparing quantities.
Go to lesson quiz →Exam guidance · WAEC WASSCE Paper 1 + Paper 2 Lens
Pacing
Objective speed on Paper 1 + structured step-by-step method marks on Paper 2 Theory/Practical.
How WAEC marks this
Examiners award method marks (M1) for stating the formula/definition and accuracy marks (A1) ONLY when SI units are written.
Watch out for
Writing bare numbers without working or omitting SI units loses up to 50% of Paper 2 marks even when the final value is right.
Lesson content
Overview — Ratios & Proportions
Sharing and comparing quantities. This lesson is at the beginner level — by the end, you'll be able to recognise this question type, apply a reliable method, and avoid the traps that cost marks.
Key Concept
A ratio compares two or more quantities. To share an amount in a given ratio, add the ratio parts together to find the total number of 'shares', then multiply the whole amount by each part's fraction of that total.
Why It's Tested This Way
Ratio and proportion questions are tested because they underlie so many real-world sharing and scaling problems — from splitting profits between business partners to scaling a recipe or a map.
Method
To simplify a ratio, divide every term by their highest common factor, just like simplifying a fraction.
Worked Example
Worked example: Sharing ₦600 in the ratio 2:3:1 (total 6 parts): each part = 600 ÷ 6 = ₦100, so the shares are ₦200, ₦300 and ₦100.
Second Worked Example
Second worked example: Sharing ₦900 in the ratio 4:5 (total 9 parts): each part = 900 ÷ 9 = ₦100, so the shares are ₦400 and ₦500.
Common Traps
Common trap: dividing the amount by one of the ratio numbers instead of by the SUM of all the ratio numbers.
Lesson Summary
Remember: (1) identify what is being asked, (2) apply the WAEC strategy, (3) check against the traps. Complete the 10-question quiz below to unlock the next lesson — you need at least 60% to pass.
Mastery Check · Lesson Quiz · pass 60%
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