Ratio Questions Explained
Ratio questions are common in numerical reasoning tests. They test your ability to compare quantities and divide amounts in proportion. Here's how to approach them.
What Is a Ratio?
A ratio compares two or more quantities. The ratio 3:2 means "for every 3 of A, there are 2 of B." Ratios can be simplified: 6:4 = 3:2 (divide both by 2). Always simplify when possible to make calculations easier.
Dividing a Quantity in a Ratio
To split a total in ratio 2:3: First add the parts: 2 + 3 = 5. Each part = total ÷ 5. Amount for first = 2 × (total ÷ 5); amount for second = 3 × (total ÷ 5). Example: £500 in 2:3 → 1 part = £100, first gets £200, second gets £300.
Finding Missing Values
If you know A:B = 3:4 and A = 12, then 1 part = 12 ÷ 3 = 4, so B = 4 × 4 = 16. Or use cross-multiplication: if A/B = 3/4, then A = (3/4) × B, so B = A ÷ (3/4) = A × (4/3).
Ratio and Percentages
A ratio of 1:3 means the first part is 1/(1+3) = 25% of the whole, and the second is 75%. Converting between ratios and percentages helps when questions mix both.
Practice Ratio Questions
Build fluency with numerical reasoning practice including the numerical reasoning test, abstract reasoning, and Watson Glaser.
Frequently Asked Questions
What's the difference between ratio and proportion?
A ratio compares quantities (e.g. 2:3). A proportion states that two ratios are equal (e.g. 2/3 = 4/6). Both appear in aptitude tests.
How do I handle ratios with more than two parts?
Same logic. For 2:3:5, total parts = 10. Each part = total ÷ 10. Multiply each ratio number by that part value.
Can ratios have decimals?
Usually they're given as whole numbers. If you get decimals, multiply by a common factor to simplify (e.g. 1.5:2 = 3:4).