Top 50 - Part 3

1. Trains

A train 150 m long travels at 54 km/h. How long will it take to pass a pole?

A) 8 sec B) 10 sec C) 12 sec D) 15 sec

Answer: B) 10 seconds

54 km/h = 15 m/s

Time = 150/15
     = 10 sec

2. Permutation

How many arrangements can be made from the letters of DOG?

A) 3 B) 6 C) 9 D) 12

Answer: B) 6

3! = 6

3. Combination

How many committees of 2 can be formed from 8 people?

A) 16 B) 24 C) 28 D) 32

Answer: C) 28

⁸C₂ = 8×7/2
    = 28

4. Probability

A coin is tossed once. What is the probability of getting a head?

A) 0 B) 1/4 C) 1/2 D) 1

Answer: C) 1/2

Possible = H, T

Favorable = 1

P(H) = 1/2

5. Probability

Two dice are thrown. What is the probability that the sum is 7?

A) 1/12 B) 1/6 C) 1/4 D) 1/3

Answer: B) 1/6

Total outcomes:

6 × 6 = 36

Sum 7:

(1,6)
(2,5)
(3,4)
(4,3)
(5,2)
(6,1)

6 favorable outcomes.

6/36 = 1/6

6. Algebra

If:

3x - 5 = 16

find x.

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

Answer: C) 7

3x - 5 = 16
3x = 21
x = 7

7. Quadratic Equation

Solve:

x² - 5x + 6 = 0

A) 1, 6 B) 2, 3 C) 3, 4 D) 2, 4

Answer: B) 2, 3

Factor:

x² - 5x + 6

= (x - 2)(x - 3)

Therefore:

x = 2 or 3

8. Geometry

The perimeter of a square is 40 cm. Find its area.

A) 80 cm² B) 90 cm² C) 100 cm² D) 120 cm²

Answer: C) 100 cm²

4 × side = 40

side = 10 cm

Area = 10²
     = 100 cm²

9. Geometry

The radius of a circle is 14 cm. Find its area using π = 22/7.

A) 484 cm² B) 616 cm² C) 628 cm² D) 700 cm²

Answer: B) 616 cm²

Area = πr²

= 22/7 × 14 × 14

= 616 cm²

10. Mensuration

Find the volume of a cube with side 5 cm.

A) 25 cm³ B) 50 cm³ C) 100 cm³ D) 125 cm³

Answer: D) 125 cm³

Volume = side³

= 5³
= 125 cm³

11. Data Interpretation

A company has the following employees:

Department	Employees
IT	240
HR	60
Finance	100
Sales	200

What percentage of the total employees work in IT?

A) 30% B) 35% C) 40% D) 45%

Answer: C) 40%

Total:

240 + 60 + 100 + 200
= 600

IT percentage:

240/600 × 100
= 40%

12. Data Interpretation

A company’s sales were:

Year	Sales
2023	₹20 lakh
2024	₹25 lakh
2025	₹30 lakh

What was the percentage increase from 2023 to 2025?

A) 25% B) 40% C) 50% D) 60%

Answer: C) 50%

Increase = 30 - 20
         = 10

Percentage = 10/20 × 100
           = 50%

13. Number Series

Find the missing number:

5, 10, 20, 40, 80, ?

A) 100 B) 120 C) 140 D) 160

Answer: D) 160

Pattern:

×2 each time

80 × 2 = 160

14. Number Series

Find the next number:

3, 6, 11, 18, 27, ?

A) 36 B) 38 C) 40 D) 42

Answer: B) 38

Differences:

+3
+5
+7
+9

Next:

+11

Therefore:

27 + 11 = 38

15. Probability

A bag contains 5 red balls and 3 blue balls. Two balls are selected without replacement. What is the probability that both are red?

A) 5/14 B) 5/16 C) 10/28 D) 1/2

Answer: A) 5/14

First red:

5/8

Second red:

4/7

Therefore:

P = 5/8 × 4/7
  = 20/56
  = 5/14

16. Mixed Aptitude

A person spends 70% of his salary. If he saves ₹9,000 per month, what is his monthly salary?

A) ₹20,000 B) ₹25,000 C) ₹30,000 D) ₹35,000

Answer: C) ₹30,000

If he spends 70%, he saves:

100% - 70% = 30%

Therefore:

30% of Salary = ₹9,000

Salary = 9000 × 100/30
       = ₹30,000

If you’re preparing for IT placement QA, don’t give all 85 questions equal importance.

Tier 1 — Master first

1. Percentages
2. Profit & Loss
3. Ratio & Proportion
4. Average
5. Time & Work
6. Time-Speed-Distance
7. Number System
8. Simple Interest
9. Probability
10. Data Interpretation

Tier 2 — Master next

11. Compound Interest
12. Discount
13. Mixtures
14. Partnership
15. Ages
16. HCF
17. LCM
18. Pipes & Cisterns
19. Boats & Streams
20. Trains
21. Permutation
22. Combination
23. Number Series
24. Algebra
25. Mensuration

Tier 3 — Complete the remaining patterns

26–50:
More variations of the core arithmetic topics

51–85:
Additional placement-level variations,
mixed problems, DI, probability,
number systems, algebra and geometry.

Important: I deliberately corrected several option/answer inconsistencies while building the set. In particular, questions 14, 15, 24, 29, 39, 61 and 66 had issues in the draft-style versions, so the mathematically correct result is stated rather than forcing an incorrect option.

For actual preparation, the best strategy is not memorizing these 85 answers. Learn the underlying pattern and shortcut for each one, because placement exams usually change the numbers while keeping the same structure. Current placement resources similarly emphasize recurring topic patterns rather than only memorizing exact questions.