In a class of 30 children, the ratio of boys to girls is 3:2. How many boys are there?
Show worked explanation
The ratio 3:2 means 5 equal parts total (3+2=5). Divide 30 by 5 = 6 per part. Boys = 3 parts = 3 × 6 = 18 boys. ✓
Ratio and proportion typically appears as two to four questions on a GL Assessment 11+ maths paper, where GL lists it as "simple ratio" within the statistics section. It covers sharing an amount in a given ratio, simplifying ratios, scaling recipes and reading map scales, plus the all-important link between ratios and fractions.
The GL maths paper is 50 multiple-choice questions in 50 minutes, with five options (A to E) per question. Ratio questions are almost always word problems, and the harder ones can need three or four calculation steps inside a single minute, so a quick, confident method matters as much as the arithmetic.
The reassuring part is that ratio rests on one core routine: add the parts, divide the total, then multiply back up. Once that becomes automatic, most GL ratio questions follow the same shape, and steady practice builds real speed and accuracy.
Every ratio question is multiple-choice with five options (A to E), almost always a word problem. In rough order of frequency, GL tests:
Difficulty ranges from simple sharing with friendly numbers (easy) to multi-step problems that work backwards from one person's share to find the total (hard). Inverse proportion is rare at 11+ and only appears in simple forms.
Five questions drawn from PrepStep’s ratio & proportion bank, spanning Foundation to Challenging. Tap “Show worked explanation” to see the full method after you’ve had a go. The correct answer is highlighted on each question so you can check immediately.
In a class of 30 children, the ratio of boys to girls is 3:2. How many boys are there?
The ratio 3:2 means 5 equal parts total (3+2=5). Divide 30 by 5 = 6 per part. Boys = 3 parts = 3 × 6 = 18 boys. ✓
Tom and Jerry share 80 marbles in the ratio 3:5. How many marbles does Jerry get?
Total parts: 3 + 5 = 8 parts. Each part = 80 ÷ 8 = 10 marbles. Jerry gets 5 parts = 5 × 10 = 50 marbles. ✓
Andrew and Matthew share 96 sweets in the ratio 5:3. How many more sweets does Andrew get than Matthew?
Total parts: 5 + 3 = 8. Each part = 96 ÷ 8 = 12. Andrew gets 5 × 12 = 60, Matthew gets 3 × 12 = 36. Difference: 60 - 36 = 24. ✓
A milkshake recipe uses 4 spoonfuls of syrup for 300ml of milk. How many spoonfuls are needed for 750ml of milk?
750ml is 2.5 times 300ml (750 ÷ 300 = 2.5). So syrup needed = 4 × 2.5 = 10 spoonfuls. ✓
A model of a building is made to scale 1:50. If the model is 60cm tall, how tall is the real building in metres?
Real height = 60 × 50 = 3000cm = 30 metres. ✓
Common mistake 1 of 4
Confusing part-to-part with part-to-whole.
Tip: The ratio 3:4 means 3 out of every 7, not 3 out of 4. Add the parts to get the whole first, then any fraction question becomes "this part out of the total".
Common mistake 2 of 4
Adding instead of multiplying (the additive error).
Tip: Seeing 2 become 6 and adding 4 to 3 to get 7, instead of multiplying by 3 to get 9. Always ask "how many times bigger?", never "how much was added?".
Common mistake 3 of 4
Giving the wrong share, or the wrong thing entirely.
Tip: Children mix up who gets which share, or give one person's share when the question asked for the total. Underline exactly what is being asked before calculating.
Common mistake 4 of 4
Not simplifying a ratio fully.
Tip: Reducing 12:18 to 6:9 and stopping, instead of going on to 2:3. After simplifying, check the parts share no further common factor.
Ratio compares quantities, written as a:b, and proportion describes a part of a whole. In the GL 11+, children share amounts in a ratio, simplify ratios, scale recipes and maps, and convert between ratios and fractions. Questions are word problems, always multiple-choice with five options.
No, and this is the single most common ratio mistake. The ratio 3:4 has 3 parts and 4 parts, making 7 parts in total, so the first quantity is 3/7 of the whole, not 3/4. Always add the parts to find the whole before writing a fraction.
Follow three steps: add the ratio parts to get the total number of parts, divide the amount by that total to find the value of one part, then multiply each ratio number by the value of one part. Finally, check the shares add back up to the original total.
Typically two to four per paper. Ratio sits within the statistics section, which is smaller than the number-heavy core of the paper, but ratio ideas also turn up inside number and money problems, so the skill is worth more than the question count suggests.
Use timed, five-option word problems that match the exam. Make the "add the parts, divide, multiply back" routine automatic first, then drill the ratio-to-fraction link (3:4 means 3/7) because GL exploits it constantly. Add three-part ratios, recipe scaling and working-backwards questions once the basics are secure.
PrepStep has 245 ratio & proportion questions in GL Assessment format: five options, instant feedback, and step-by-step explanations. Free to start.
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