1. Write the ratio 8 : 12 in its simplest form.
- A2 : 3
- B3 : 2
- C4 : 6
- D8 : 12
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Answer: A) 2 : 3
Divide both terms by the HCF 4: = 2 and = 3, so 8 : 12 = 2 : 3.
Class 8 Ratios and Proportions — practice questions with answers
Comparing Quantities · 5 sample questions from the school syllabus. Try each one, then open the answer and the worked solution.
2. Two numbers are in the ratio 5 : 7 and their sum is 96. The smaller number is:
- A40
- B80
- C36
- D44
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Answer: A) 40
Total parts = 5 + 7 = 12. Each part = = 8. Smaller number = 5 * 8 = 40.
3. In a proportion a : b :: c : d, the terms b and c are called the:
- Ameans
- Bextremes
- Cantecedents
- Dconsequents
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Answer: A) means
In a : b :: c : d, the inner terms b and c are the means and the outer terms a and d are the extremes.
4. If a : b = 2 : 3 and b : c = 6 : 7, find a : b : c in simplest form.
- A4 : 6 : 7
- B2 : 3 : 7
- C2 : 6 : 7
- D4 : 6 : 14
Show answer
Answer: A) 4 : 6 : 7
Make b common. a : b = 2 : 3 = 4 : 6 and b : c = 6 : 7. So a : b : c = 4 : 6 : 7.
5. The ratio of the number of Rs 5 coins to Rs 2 coins in a box is 3 : 5, and the total value of all coins is Rs 150.
Find the number of Rs 2 coins.
Find the number of Rs 2 coins.
- A30
- B33
- C27
- D60
Show answer
Answer: A) 30
Let coins be 3k (Rs 5) and 5k (Rs 2). Value = 5(3k) + 2(5k) = 15k + 10k = 25k = 150, so k = 6. Rs 2 coins = 5 * 6 = 30.
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