Class 8 Maths – Chapter 13
Direct and Inverse Proportions
STEP 9: Worksheet FULL ANSWERS
Direct and Inverse Proportions
STEP 9: Worksheet FULL ANSWERS
📝 Instructions:
• Read each solution step carefully
• Learn the method, not just the answer
• Read each solution step carefully
• Learn the method, not just the answer
✔️ Solutions
-
Cost of notebooks
5 notebooks = ₹75
Cost of 1 notebook = 75 ÷ 5 = ₹15
Cost of 12 notebooks = 12 × 15 = ₹180 -
Workers and days (Inverse proportion)
8 workers × 15 days = 120
Days required by 12 workers = 120 ÷ 12 = 10 days -
Petrol and distance (Direct proportion)
20 litres → 300 km
1 litre → 300 ÷ 20 = 15 km
35 litres → 35 × 15 = 525 km -
Time and distance (Direct proportion)
3 hours → 180 km
1 hour → 60 km
5 hours → 5 × 60 = 300 km -
Men and days (Inverse proportion)
6 men × 10 days = 60
Days for 15 men = 60 ÷ 15 = 4 days -
Identify proportion
a) Students & total marks → Direct
b) Speed & time → Inverse
c) Workers & time → Inverse -
Direct proportion
x ∝ y → x/y = constant
24/6 = 4
When y = 10, x = 10 × 4 = 40 -
Inverse proportion
x × y = constant
8 × 4 = 32
When x = 16, y = 32 ÷ 16 = 2
🎯 Exam Tip:
• Always mention type of proportion
• Write formula before calculation
• Neat steps = full marks
• Always mention type of proportion
• Write formula before calculation
• Neat steps = full marks
📘 Class 8 Mathematics – Complete Library
CBSE | NCERT | State Syllabus
Chapter 1: Rational Numbers
Chapter 2: Linear Equations in One Variable
Chapter 3: Understanding Quadrilaterals
Chapter 4: Practical Geometry
Chapter 5: Data Handling
Chapter 6: Squares and Square Roots
Chapter 7: Cubes and Cube Roots
- NCERT Notes
- MCQs
- Worksheet
- Worksheet Answers
- Mind Map & Easy Tricks
- Important Exam Questions
- Very Important Questions
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