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Series Completion - General Inteligence & Reasoning MCQ Questions and Answers

Learn Series Completion mcq questions and answers with easy and logical explanations - Series Completion is part of competitive reasoning mcq questions.

Each section contains 100 MCQs on Series Completion .
1
120, 99, 80, 63, 48, ?
Discuss
Answer & Solution
Answer: Option A
Solution:
The pattern is - 21, - 19, - 17, - 15,.....
So, missing term = 48 - 13 = 35.
2
589654237, 89654237, 8965423, 965423, ?
Discuss
Answer & Solution
Answer: Option D
Solution:
The given series is: 589654237, 89654237, 8965423, 965423, ?
Step 1: Observe the pattern in the series.
Step 2: The first number 589654237 loses the first digit '5' to become 89654237.
Step 3: The second number 89654237 loses the last digit '7' to become 8965423.
Step 4: The third number 8965423 loses the first digit '8' to become 965423.
Step 5: The fourth number 965423 loses the last digit '3' to become 96542.
Pattern Observed: The series alternates between removing the first digit and the last digit.
Final Step: Following this pattern, the next number after 965423 should be 96542 (removing the last digit '3').
Thus, the correct answer is: 96542 (Option D).
3
3, 10, 101, ?
Discuss
Answer & Solution
Answer: Option C
Solution:
Each term in the series is obtained by adding 1 to the square of the preceding term.
So, missing term = (101)2 + 1 = 10202.
4
In the series 2, 6, 18, 54, ...... what will be the 8th term ?
Discuss
Answer & Solution
Answer: Option B
Solution:
Clearly, 2 x 3 = 6, 6 x 3 = 18, 18 x 3 = 54,.....
So, the series is a G.P. in which a = 2, r = 3.
Therefore 8th term = ar8-1 = ar7 = 2 x 37 = (2 x 2187) = 4374.
5
125, 80, 45, 20, ?
Discuss
Answer & Solution
Answer: Option A
Solution:
The pattern is - 45, - 35, - 25, .....
So, missing term = 20 - 15 = 5.
6
1, 1, 4, 8, 9, 27, 16, ?
Discuss
Answer & Solution
Answer: Option B
Solution:
The series consists of squares and cubes of consecutive natural numbers i.e. 12, 13, 22, 23, 32, 33, 42, .....
So, missing term = 43 = 64.
7
1, 2, 3, 6, 9, 18, ?, 54
Discuss
Answer & Solution
Answer: Option B
Solution:
Let's break down this number series question!

The series is: 1, 2, 3, 6, 9, 18, ?, 54

Look for a pattern. It's not a simple addition or subtraction.

Notice this:
1 + 2 = 3
3 + 6 = 9
9 + 18 = ?

It looks like each number is the sum of the two numbers before it.

So, to find the missing number: 9 + 18 = 27

Therefore, the missing number is 27. The correct answer is B.

Double-check: 18 + 27 = 45 (Incorrect so that Logic is wrong)

Notice this new Logic:
1 x 2 = 2
2 x (3/2) = 3
3 x 2 = 6
6 x (3/2) = 9
9 x 2 = 18
18 x (3/2) = ?
So, to find the missing number: 18 x (3/2) = 27
Then check it with the next number: 27 x 2 = 54

Therefore, the missing number is 27. The correct answer is B.
8
6, 13, 25, 51, 101, ?
Discuss
Answer & Solution
Answer: Option C
Solution:
The pattern is x 2 + 1, x 2 - 1, x 2 + 1, x 2 - 1,.....
So, missing term = 101 x 2 + 1 = 203.
9
5, 6, 9, 15, ?, 40
Discuss
Answer & Solution
Answer: Option B
Solution:
The pattern is + 1, + 3, + 6,....., i.e. + 1, + (1, + 2), + (1 + 2 + 3),.....
So, missing term = 15 + (1 + 2 + 3 + 4) = 25.
10
1, 3, 4, 8, 15, 27, ?
Discuss
Answer & Solution
Answer: Option C
Solution:
The sum of any three consecutive terms of the series gives the next term.
So, missing number = 8 + 15 + 27 = 50.