SSC CGL Percentage Concept Check

1. 84 is what percentage of 560?

• A. 12%
• B. 15% (Correct)
• C. 18%
• D. 20%

Explanation: Use 560 as the base: 84/560 × 100 = 15%. Check: 10% of 560 is 56 and 5% is 28, giving 84.

2. A library reserves 18% of 650 new books for a reading programme. How many books are reserved?

• A. 107
• B. 117 (Correct)
• C. 127
• D. 137

Explanation: 18/100 × 650 = 117. Alternatively, 20% is 130 and 2% is 13. Subtract to obtain 117 books.

3. After a 25% discount, a desk costs Rs. 930. What was its marked price?

• A. Rs. 1162.50
• B. Rs. 1200
• C. Rs. 1240 (Correct)
• D. Rs. 1395

Explanation: The paid amount is 75% of marked price M. Thus 0.75M = 930 and M = 1240. Adding 25% to 930 does not reverse the discount.

4. A quantity rises by 12% and then falls by 12%. What is the net change from its starting value?

• A. No change
• B. 1.44% decrease (Correct)
• C. 1.44% increase
• D. 2.4% decrease

Explanation: Start with 100. It becomes 112, then 112 × 0.88 = 98.56. The loss is 1.44 on the original base 100, or 1.44%.

5. A town has 10,000 residents. Population increases by 8% in one year and 10% in the next. Find the final population.

• A. 11800
• B. 11880 (Correct)
• C. 11900
• D. 12000

Explanation: Apply both multipliers: 10000 × 1.08 × 1.10 = 11880. The second increase is 10% of 10800, not of the original 10000.

6. Unit price increases by 25%. By what percentage must quantity purchased decrease to keep expenditure unchanged?

• A. 15%
• B. 20% (Correct)
• C. 25%
• D. 30%

Explanation: The price multiplier is 1.25. The quantity multiplier must be 1/1.25 = 0.80. Quantity falls by 20%, since 1.25 × 0.80 = 1.

7. A is 40% greater than B. By what percentage is B less than A, rounded to two decimal places?

• A. 28.57% (Correct)
• B. 40.00%
• C. 60.00%
• D. 71.43%

Explanation: Let B = 100 and A = 140. The difference is 40, using A as the base. Then 40/140 × 100 = 28.5714...%, rounding to 28.57%.

8. An interest rate rises from 12% to 15%. What is the relative percentage increase in the rate?

• A. 3%
• B. 12%
• C. 20%
• D. 25% (Correct)

Explanation: The difference is 3 percentage points. Relative to the original rate, 3/12 × 100 = 25%. The question asks a relative change, not percentage points.

9. In an election between two candidates, all 1800 votes cast are valid. The winner receives 56%. What is the winning margin?

• A. 108 votes
• B. 180 votes
• C. 216 votes (Correct)
• D. 1008 votes

Explanation: The loser has 44% of valid votes. The margin is (56 − 44)% of 1800 = 216 votes. The winner's total alone is not the margin.

10. The pass mark is 60% of the maximum. A student scores 174 and falls short by 6 marks. Find the maximum marks.

• A. 280
• B. 290
• C. 300 (Correct)
• D. 320

Explanation: Passing requires 174 + 6 = 180. Since this is 60% of maximum M, M = 180/0.60 = 300. Do not use 174 as the passing score.

11. Monthly income is Rs. 22,500 and expenditure is Rs. 18,000. Income rises by 20% and expenditure by 10%. By what percentage do savings rise?

• A. 10%
• B. 20%
• C. 40%
• D. 60% (Correct)

Explanation: Old savings = 4500. New income = 27000 and expenditure = 19800, leaving 7200. The increase is 2700; 2700/4500 × 100 = 60%.

12. A rectangle's length increases by 15% and width decreases by 20%. What is the percentage change in area?

• A. 5% decrease
• B. 8% decrease (Correct)
• C. 8% increase
• D. 35% decrease

Explanation: Area is length times width, so its multiplier is 1.15 × 0.80 = 0.92. New area is 92% of the original: an 8% decrease.

13. A 50 kg batch contains 80% water. Only water is removed until the remaining batch contains 60% water. Find its remaining mass.

• A. 20 kg
• B. 25 kg (Correct)
• C. 30 kg
• D. 40 kg

Explanation: Dry material remains 20% of 50 = 10 kg. It is now 40% of final mass M. Hence 0.40M = 10, giving M = 25 kg.

14. What single discount is equivalent to successive discounts of 10% and 20%?

• A. 18%
• B. 28% (Correct)
• C. 30%
• D. 32%

Explanation: The retained fraction is 0.90 × 0.80 = 0.72. The discounted fraction is 1 − 0.72 = 0.28, so the equivalent discount is 28%.

15. A value rises by 25%. What percentage reduction of the new value restores the original?

• A. 16%
• B. 20% (Correct)
• C. 25%
• D. 30%

Explanation: An original value of 100 becomes 125. The fall needed is 25, measured against 125: 25/125 × 100 = 20%.