Worksheets › Class 8 › Proportional Reasoning: Thinking Puzzles
Class 8 · Computational Thinking and AI worksheetProportional Reasoning: Thinking Puzzles
CBSE Computational Thinking and AI. Sharing in a ratio, mixtures, direct and inverse proportion, map scales, stacking blocks under rules. Every sheet has 20 questions in three sections and an answer key, and the questions change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
Two ratios a : b and c : d are in proportion when:
- a × b = c × d
- a − b = c − d
- a + d = b + c
- a × d = b × c
Answer
(d) a × d = b × c
- 2.
₹779 is shared in the ratio 4 : 7 : 8. What is the largest share (in ₹)?
- 328
- 164
- 259
- 369
Answer
(a) 328
779 ÷ 19 = 41 per part; × 8
- 3.
A jug has 9 litres of milk and water in the ratio 2 : 1. 3 litres of water are added. What is the new ratio of milk to water?
- 3 : 1
- 2 : 4
- 2 : 1
- 1 : 1
Answer
(d) 1 : 1
milk 6 L, water 3 + 3 = 6 L; 6 : 6 = 1 : 1
Section B · short answer
- 4.
What is the difference between direct and inverse proportion? Give one example of each.
Answer
Direct: both grow together (cost and number of pens); inverse: one grows as the other shrinks (workers and days).
- 5.
Divide ₹429 in the ratio 4 : 7 : 2. Write the three shares in order.
Answer
₹132, ₹231, ₹66
429 ÷ 13 = 33 per part
Section C · long answer
- 6.
A can holds 20 litres of milk and water in the ratio 3 : 1. (a) How much milk is there? (b) How much water? (c) How much water must be added to make the ratio 3 : 5?
Answer
(a) 15 litres; (b) 5 litres; (c) 20 litres
20 ÷ 4 = 5 per part; new water 5 × 5 = 25
Fresh sheets for your child
In the app, every Proportional Reasoning: Thinking Puzzles sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.