Extra Questions: Class 8 Maths Chapter 7 Proportional Reasoning-1

Practice questions beyond the textbook exercises, testing deeper understanding of ratio and proportion for Class 8 Maths Chapter 7: Proportional Reasoning-1. These Class 8 Mathematics Chapter 7 important questions are handy for last-minute exam practice.

Last Updated: September 23, 2026

Extra Questions: Class 8 Maths Chapter 7 Proportional Reasoning-1

1. 1 (Assertion-Reason). Assertion: 6:9 and 10:15 are in proportion. Reason: Both ratios simplify to 2:3.
   Solution: Both true, and the reason correctly explains the assertion — 6:9 = 2:3 and 10:15 = 2:3, so the two ratios are equal.
2. 2 (Numerical). A car covers 180 km in 3 hours. At the same speed, how far will it travel in 5 hours?
   Solution: Speed = 180÷3 = 60 km/h. Distance in 5 hours = 60×5 = 300 km.
3. 3 (Short Answer). Are the ratios 5:8 and 8:5 the same?
   Solution: No — order matters in a ratio. 5:8 and 8:5 are reciprocals of each other and represent different comparisons, not the same relationship.
4. 4 (Applied). Two numbers are in the ratio 3:4, and their sum is 84. Find the numbers.
   Solution: Total parts = 3+4 = 7; each part = 84÷7 = 12. The numbers are 36 and 48.
5. 5 (Assertion-Reason). Assertion: If a:b = c:d, then a:c = b:d also holds. Reason: This follows because a:b=c:d means ad=bc, which is the same condition needed for a:c=b:d.
   Solution: Both true, and the reason correctly explains the assertion — both proportions reduce to the same cross-product equation, ad=bc.
6. 6 (Numerical). A recipe needs flour and sugar in the ratio 5:2 to make a 350 g mix. Find the quantity of each.
   Solution: Total parts = 7; each part = 350÷7 = 50 g. Flour = 250 g, Sugar = 100 g.
7. 7 (Synthesis). If a:b = 2:3 and b:c = 4:5, find a:b:c.
   Solution: Make b common: a:b = 2:3 = 8:12, and b:c = 4:5 = 12:15. So a:b:c = 8:12:15.
8. 8 (Applied). A map has a scale of 1:50,000. Two towns are 8 cm apart on the map. Find the actual distance in km.
   Solution: 8×50,000 = 4,00,000 cm = 4,000 m = 4 km.
9. 9 (Short Answer). Why must both terms of a ratio be in the same unit before simplifying it?
   Solution: A ratio compares two quantities as pure numbers. If the units differ (e.g. 2 m to 50 cm), they must first be converted to a common unit (2 m = 200 cm) before the ratio (200:50 = 4:1) is meaningful.
10. 10 (Assertion-Reason). Assertion: Dividing ₹600 in the ratio 1:2:3 gives ₹100, ₹200, and ₹300. Reason: The parts must add up to the total, and since 1+2+3=6 parts, each part = ₹600÷6 = ₹100.
    Solution: Both true, and the reason correctly explains the assertion — 1×100=100, 2×100=200, 3×100=300, and these sum to ₹600.

Frequently Asked Questions

If the cost of a certain number of items is known, how can direct proportion be used to find the cost of a different quantity?
The cost per single item is found by dividing the total cost by the given quantity, and multiplying that cost per item by the new required quantity gives the answer.

How can you tell from a graph whether two quantities are in direct proportion?
If two quantities are in direct proportion, plotting their corresponding values produces a straight line passing through the origin, since their ratio remains constant throughout.

Written by Satish

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