Weighted Average
SSC GD Exam Preparation - Quantitative Aptitude
🔹 1. What is Weighted Average?
When different items do not have equal importance/quantity, we use weighted average.
👉 It is the average in which each value has a weight.
🔹 2. Weighted Average Formula
Weighted Average = (w₁x₁ + w₂x₂ + w₃x₃ + ...) / (w₁ + w₂ + w₃ + ...)
Where:
- • x₁, x₂... are values
- • w₁, w₂... are weights
Key Point:
Weights represent the importance or quantity of each value in the average calculation.
🔹 3. When is Weighted Average Used?
- ✔ Marks in exams with different weightage
- ✔ Average speed (different distances)
- ✔ Salary of groups
- ✔ Cost price of mixed goods
- ✔ Population or score comparisons
- ✔ Any scenario with unequal quantities
🔹 4. Key Shortcut
If two items are mixed:
Weighted Average = (a × m + b × n) / (m + n)
🔹 5. Examples
Example 1
A student scores: Maths 80 (weight 3), English 60 (weight 2)
(80×3 + 60×2)/(3+2) = (240 + 120)/5 = 72
Example 2 (Cost Price)
Rice ₹40 (10 kg), ₹50 (5 kg)
(40×10 + 50×5)/(10+5) = (400 + 250)/15 = 43.33
Example 3 (Speed)
A man travels: 40 km at 20 km/h, 60 km at 30 km/h
(40 + 60)/(40/20 + 60/30) = 100/(2+2) = 25 km/h
🧠 Practice Section: 15 Weighted Average Questions (With Answers)
Test your weighted average concepts with these SSC GD level practice questions. Click on "View Answer" to check your understanding.
Q1. Find the weighted average of 10, 20, 30 with weights 1, 2, 3.
View Answer
(10×1 + 20×2 + 30×3)/(1+2+3) = (10 + 40 + 90)/6 = 23.33
Q2. Price of sugar: ₹40 (6 kg) and ₹50 (4 kg). Find average price.
View Answer
(40×6 + 50×4)/10 = (240 + 200)/10 = 44
Q3. A student scores 70 (weight 3) and 90 (weight 1). Find weighted avg.
View Answer
(70×3 + 90×1)/4 = (210 + 90)/4 = 75
Q4. Two groups: 30 students avg 60 marks, 20 students avg 40 marks. Find overall avg.
View Answer
(30×60 + 20×40)/50 = (1800 + 800)/50 = 52
Q5. Milk prices: ₹30 (8 L) & ₹40 (2 L). Find average price.
View Answer
(240 + 80)/10 = ₹32
Q6. Avg salary: 5 workers = ₹20,000; 3 workers = ₹30,000. Find combined avg.
View Answer
(5×20000 + 3×30000)/8 = (100000 + 90000)/8 = 23750
Q7. Find weighted average of 15 & 25 with weights 4 & 6.
View Answer
(15×4 + 25×6)/10 = (60 + 150)/10 = 21
Q8. Two classes: Class A: avg = 50 (20 students), Class B: avg = 70 (30 students). Find combined avg.
View Answer
(50×20 + 70×30)/50 = (1000 + 2100)/50 = 62
Q9. Prices: ₹60 (3 kg), ₹90 (7 kg). Find avg price.
View Answer
(180 + 630)/10 = 81
Q10. A student scored: 80 (weight 5), 60 (weight 1). Weighted avg?
View Answer
(80×5 + 60×1)/6 = (400 + 60)/6 = 76.67
Q11. Two items: ₹50 (2 kg), ₹70 (3 kg). Weighted average?
View Answer
(100 + 210)/5 = 62
Q12. Two groups: Avg age 24 (25 people), 30 (15 people). Find overall avg age.
View Answer
(24×25 + 30×15)/40 = (600 + 450)/40 = 26.25
Q13. Find weighted average of 5, 10, 15 with weights 2, 3, 5.
View Answer
(5×2 + 10×3 + 15×5)/10 = (10 + 30 + 75)/10 = 11.5
Q14. Speed: 20 km at 10 km/h, 30 km at 15 km/h. Find average speed.
View Answer
Time = 2 + 2 = 4 hr, Avg speed = 50/4 = 12.5 km/h
Q15. Rice: ₹45 (12 kg), ₹55 (8 kg). Find avg price.
View Answer
(540 + 440)/20 = 49
✅ SSC GD Exam Strategy
🟢 Remember weighted average formula for different scenarios
🟢 Practice two-item mixing problems using the shortcut formula
🟢 Master group average combinations (students, workers, etc.)
🟢 Learn to handle price mixture problems with different quantities
🟢 Time yourself - aim for 45-60 seconds per weighted average question
You've completed Weighted Average Concepts!
SSC GD Tip: Weighted average problems test your ability to handle unequal quantities and importance. Focus on mastering the basic formula and the two-item mixing shortcut. Remember that weights can represent quantities, frequencies, or importance levels. Practice different scenarios like price mixtures, group averages, and weighted scores as they frequently appear in SSC exams. Regular practice with previous year questions will build your speed and accuracy in solving weighted average problems efficiently.
Master Weighted Average for SSC GD Exam!
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