Quantitative Aptitude: Quiz on Number Series

Dear readers,

In Banking and Insurance examinations, in Quantitative Aptitude, questions from Number series are frequently asked. Such questions test a candidate’s decision-making ability and speed using limited input. 

The quiz on Number series provided here, will help you prepare for the upcoming exams.  Please try to give answers in the comment box; soon we will publish the correct answers.

Directions
(1-5):
In the
following number series, a wrong
number is given. Find out the wrong number.

1. 29,
37, 21, 43, 13, 53, 5

(1) 37

(2) 53

(3) 13

(4) 21

(5) 43                                             

2. 600,
125, 30, 13, 7.2, 6.44, 6.288           

(1) 125

(2) 30

(3) 13

(4) 6.44

(5) 7.2

3. 80,
42, 24, 13.5, 8.75, 6.375, 5.1875

(1) 8.75

(2) 13.5

(3) 24

(4) 6.375

(5) 42

4. 10,
8, 13, 35, 135, 671, 4007

(1) 8

(2) 671

(3) 135

(4) 13

 (5) 35

5. 150,
290, 560, 1120, 2140, 4230, 8400

(1) 2140

(2) 4230

(3) 560

(4) 290

(5) 1120

Answers:

Qs 1 (5)   
Qs 2 (3)    Qs 3 (3)   Qs 4 (2)  
Qs 5 (5)

Solutions:

1.
29,
37, 21, 43, 13, 53, 5

29 – 8 = 21,  

21 – 8 = 13,

13 – 8 = 5

37 +8 = 45

45 + 8 = 53

So wrong number in the series is 43

2.
600,
125, 30, 13, 7.2, 6.44, 6.288           

6.288 x 5 – (5×5) = 6.44

6.44 x 5 – (5×5) = 7.2

7.2 x 5 – (5×5) = 11

11 x 5 – (5×5) = 30

30 x 5 – (5×5) = 125

125 x 5 – (5×5) = 600

So wrong number in the series is 13

3.
80,
42, 24, 13.5, 8.75, 6.375, 5.1875

5.1875 x 2 – (2×2) = 6.375

6.375 x 2 – (2×2) = 8.75

8.75 x 2 – (2×2) = 13.5

13.5 x 2 – (2×2) = 23

24 x 2 – (2×2) = 42

42 x2 – (2×2) = 80

So wrong number in the series is 24.

4.
10,
8, 13, 15, 35, 135, 671, 4007

10 x1 – 2 = 8

8 x2 – 3 = 13

13 x3 – 4 = 35

35 x4 – 5 = 135

135 x 5 – 6 = 669

669 x 6 – 7 = 4007

So wrong number in the series is 671

5.
150,
290, 560, 1120, 2140, 4230, 8400

150 x2 – 10 = 290

290 x 2 – 20 = 560

560 x 2 – 30 = 1090

1090 x2 – 40 = 2140

So wrong number in the series is 1120.

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