Top 10 Quantitative Aptitude Questions

1. Percentage

A number is increased by 20% and then decreased by 20%. What is the overall percentage change?

A) No change B) 2% decrease C) 4% decrease D) 4% increase

Answer: C) 4% decrease

Explanation:

Take the number as 100.

100 + 20% = 120

20% of 120 = 24

120 - 24 = 96

Decrease = 100 - 96 = 4

Therefore:

Percentage decrease = 4%

Shortcut:

Net change = -20² / 100
           = -4%

2. Profit and Loss

A shopkeeper buys an article for ₹800 and sells it for ₹920. Find the profit percentage.

A) 10% B) 12% C) 15% D) 20%

Answer: C) 15%

Explanation:

CP = ₹800
SP = ₹920

Profit = 920 - 800
       = ₹120

Profit % = 120/800 × 100
         = 15%

3. Ratio and Proportion

The ages of A and B are in the ratio 3:5. Their total age is 40 years. Find B’s age.

A) 15 B) 20 C) 25 D) 30

Answer: C) 25 years

Explanation:

A : B = 3 : 5

Total parts = 8

1 part = 40/8 = 5

B = 5 × 5 = 25

4. Average

The average of 5 numbers is 24. Four numbers are 18, 22, 25 and 30. Find the fifth number.

A) 20 B) 22 C) 25 D) 28

Answer: C) 25

Explanation:

Total = Average × Number
      = 24 × 5
      = 120

Known total:

18 + 22 + 25 + 30 = 95

Fifth number:

120 - 95 = 25

5. Time and Work

A can complete a work in 12 days and B can complete it in 18 days. How many days will they take together?

A) 6 B) 7.2 C) 8 D) 9

Answer: B) 7.2 days

Explanation:

A's work/day = 1/12
B's work/day = 1/18

Together = 1/12 + 1/18
         = 3/36 + 2/36
         = 5/36

Time:

36/5 = 7.2 days

Shortcut:

Together = (12 × 18)/(12 + 18)
         = 7.2 days

6. Time, Speed and Distance

A car travels 180 km in 3 hours. What is its average speed?

A) 50 km/h B) 60 km/h C) 70 km/h D) 80 km/h

Answer: B) 60 km/h

Explanation:

Speed = Distance / Time

      = 180/3

      = 60 km/h

7. Number System

What is the smallest number that must be added to 578 to make it divisible by 9?

A) 5 B) 6 C) 7 D) 8

Answer: C) 7

Explanation:

Digit sum:

5 + 7 + 8 = 20

Next multiple of 9:

27

Therefore:

27 - 20 = 7

Check:

578 + 7 = 585
5 + 8 + 5 = 18

18 is divisible by 9.

8. Simple Interest

₹5,000 is invested at 8% simple interest for 3 years. Find the interest.

A) ₹800 B) ₹1,000 C) ₹1,200 D) ₹1,400

Answer: C) ₹1,200

Explanation:

SI = P × R × T / 100

   = 5000 × 8 × 3 / 100

   = ₹1,200

9. Probability

A fair die is thrown once. What is the probability of getting an even number?

A) 1/6 B) 1/3 C) 1/2 D) 2/3

Answer: C) 1/2

Explanation:

Possible:

1  2  3  4  5  6

Even:

2, 4, 6

Therefore:

P = 3/6 = 1/2

10. Data Interpretation

Year	Employees
2022	120
2023	150
2024	180
2025	200

What was the percentage increase from 2022 to 2025?

A) 50% B) 60% C) 66.67% D) 80%

Answer: C) 66.67%

Explanation:

Increase = 200 - 120 = 80

Percentage = 80/120 × 100
           = 66.67%