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Article on Number Series:
Number series is an important topic in the quantitative aptitude section of various defence exams. A number series is a sequence of numbers arranged in a specific order with a logical pattern. The pattern can be based on simple arithmetic operations such as addition, subtraction, multiplication, or division, or it can be based on more complex mathematical concepts such as square roots, cube roots, and so on. In this article, we will be discussing 20 questions on number series, each question having four options to choose from. At the end of the questions, we will provide the correct answers.
1.2, 4, 6, 8, ?
A. 10
B. 11
C. 12
D. 14
Answer: A (10)
Explanation: The pattern here is adding 2 to the previous number, so the next number is 8+2 = 10.
2.3, 6, 9, 12, ?
A. 14
B. 15
C. 18
D. 21
Answer: C (18)
Explanation: The pattern here is adding 3 to the previous number, so the next number is 12+3 = 15, and so on.
3.5, 10, 15, 20, ?
A. 25
B. 30
C. 35
D. 40
Answer: B (30)
Explanation: The pattern here is adding 5 to the previous number, so the next number is 20+5 = 25, and so on.
4.1, 4, 9, 16, ?
A. 25
B. 28
C. 36
D. 49
Answer: A (25)
Explanation: The pattern here is squaring the natural numbers starting from 1, so the next number is 5^2 = 25.
5.1, 3, 7, 15, ?
A. 25
B. 31
C. 33
D. 35
Answer: B (31)
Explanation: The pattern here is adding 2, then 4, then 8, so the next number is 15+16 = 31.
6.10, 9, 7, 4, ?
A. 0
B. -1
C. -2
D. -3
Answer: C (-2)
Explanation: The pattern here is subtracting 1, then subtracting 2, then subtracting 3, so the next number is 4-4 = 0, and so on.
7.144, 121, 100, 81, ?
A. 64
B. 49
C. 36
D. 25
Answer: B (49)
Explanation: The pattern here is taking the square of the first ten natural numbers in reverse order, so the next number is 7^2 = 49.
8.2, 4, 8, 16, ?
A. 24
B. 32
C. 36
D. 64
Answer: B (32)
Explanation: The pattern here is multiplying the previous number by 2, then 2 again, then 2 again, so the next number is 16*2 = 32.
9.5, 10, 20, 40, ?
A. 60
B. 80
C. 100
D. 120
Answer: B (80)
Explanation: The pattern here is multiplying the previous number by 2, so the next number is 40*2 = 80.
10.1, 1, 2, 3, ?
A. 4
B. 5
C. 6
D. 7
Answer: B (5)
Explanation: The pattern here is adding the previous two numbers, so the next number is 2+3 = 5.
11.10, 8, 6, 4, ?
A. 1
B. 2
C. 3
D. 5
Answer: B (2)
Explanation: The pattern here is subtracting 2 from the previous number, so the next number is 4-2 = 2.
12.3, 9, 27, 81, ?
A. 162
B. 243
C. 324
D. 729
Answer: D (729)
Explanation: The pattern here is multiplying the previous number by 3, so the next number is 81*3 = 243, and so on.
13.5, 8, 12, 17, ?
A. 20
B. 21
C. 22
D. 23
Answer: D (23)
Explanation: The pattern here is adding 3, then adding 4, then adding 5, so the next number is 17+6 = 23.
14.1, 4, 9, 16, 25, ?
A. 30
B. 36
C. 40
D. 49
Answer: D (49)
Explanation: The pattern here is squaring the natural numbers starting from 1, so the next number is 6^2 = 36, and so on.
15.7, 11, 13, 17, ?
A. 18
B. 19
C. 21
D. 23
Answer: D (23)
Explanation: The pattern here is adding 4, then adding 2, then adding 4 again, so the next number is 17+6 = 23.
16.12, 10, 8, 6, ?
A. 3
B. 2
C. 1
D. 0
Answer: A (3)
Explanation: The pattern here is subtracting 2, then subtracting 2 again, so the next number is 6-2 = 4, and so on.
17.1, 5, 13, 25, ?
A. 37
B. 41
C. 49
D. 61
Answer: C (49)
Explanation: The pattern here is adding 4, then adding 8, then adding 12, so the next number is 25+16 = 41, and so on.
18.2, 3, 5, 7, ?
A. 9
B. 10
C. 11
D. 13
Answer: D (13)
Explanation: The pattern here is taking the prime numbers starting from 2, so the next number is 11, and so on.
19.12, 9, 6, 3, ?
A. 0
B. -3
C. -6
D. -9
Answer: B (-3)
Explanation: The pattern here is subtracting 3, then subtracting 3 again, so the next number is 3-3 = 0.
20.1, 2, 6, 24, ?
A. 96
B. 120
C. 144
D. 192
Answer: B (120)
Explanation: The pattern here is multiplying by the previous number and adding 2, so the next number is 24*5 + 2 = 122, and so on.
Conclusion:
Number series is an important topic in many competitive exams, including defence exams. Practicing such questions helps to develop analytical skills and improves problem-solving ability. It is important to recognize the pattern or rule that governs the series to solve such questions quickly and accurately. By practicing more and more questions, students can gain proficiency in this topic and increase their chances of scoring well in the defence exams.
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