Directions: Each of the questions given below is followed by series of options among which you have to choose the best one. You can also review your choices by clicking into answer section.
16. Insert the missing number 4, -8, 16, -32, 64, (….)
A.128
B.-128
C.192
D.-192
Answer
Explanation:
Each number is the proceeding number multiplied by -2.
So, the required number is -128.
17. Find out the wrong number in the series : 3, 7, 15, 39, 63, 127, 255, 511
A. 7
B. 15
C. 39
D. 63
Answer
Explanation:
Go on multiplying 2 and adding 1 to get the next number.
So, 39 is wrong.
18. Insert the missing number 15, 31, 63, 127, 255, (….)
A.513
B.511
C.517
D.523
Answer
Explanation:
Each number is double the preceding one plus 1.
So, the next number is (255 x 2) + 1 = 511.
19. Find the odd man out 2, 5, 10, 17, 26, 37, 50, 64
A 50
B. 37
C. 26
D. 64
Answer
Explanation:
(1*1)+1 , (2*2)+1 , (3*3)+1 , (4*4)+1 , (5*5)+1 , (6*6)+1 , (7*7)+1 , (8*8)+1
But, 64 is out of pattern.
20. Find out the wrong number in the series 196, 169, 144, 121, 100, 80, 64
A.169
B.144
C.121
D. 80
Answer
Explanation:
Numbers must be (14)2, (13)2, (12)2, (11)2, (10)2, (9)2, (8)2.
So, 80 is wrong.
21. Find out the wrong number in the series 7, 8, 18, 57, 228, 1165, 6996
A. 8
B. 18
C. 57
D. 228
Answer
Explanation:
Let the given numbers be A, B, C, D, E, F, G.
Then, A, A x 1 + 1, B x 2 + 2, C x 3 + 3, D x 4 + 4, E x 5 + 5, F x 6 + 6 are the required numbers.
Clearly, 228 is wrong.
22. Find out the wrong number in the series 190, 166, 145, 128, 112, 100, 91
A.100
B.166
C.145
D.128
E. 112
Answer
Explanation:
Go on subtracting 24, 21, 18, 15, 12, 9 from the numbers to get the next number.
190 – 24 = 166
166 – 21 = 145
145 – 18 = 127 [Here, 128 is placed instead of 127]
127 – 15 = 112
112 – 12 = 100 … and so on.
Therefore, 128 is wrong.
23. Insert the missing number.8, 7, 11, 12, 14, 17, 17, 22, (….)
A 20
B. 22
C. 24
D. 27
Answer
Explanation:
There are two series (8, 11, 14, 17, 20) and (7, 12, 17, 22) increasing by 3 and 5 respectively.
24. Find out the wrong number in the series 15, 16, 34, 105, 424, 2124, 12756
A.16
B.34
C.105
D. 2124
Answer
Explanation:
2nd term = (1st term) x 1 + 1 = 15 x 1 + 1 = 16.
3rd term = (2nd term) x 2 + 2 = 16 x 2 + 2 = 34.
4th term = (3th term) x 3 + 3 = 34 x 3 + 3 = 105.
5th term = (4th term) x 4 + 4 = 105 x 4 + 4 = 424
6th term = (5th term) x 5 + 5 = 424 x 5 + 5 = 2125
6th term should 2125 instead of 2124.
25. Find out the wrong number in the given sequence of numbers 6, 13, 18, 25, 30, 37, 40
A 25
B. 30
C. 37
D. 40
Answer
Explanation:
The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5.
So, 40 is wrong.
26. Find out the wrong number in the series 6, 12, 48, 100, 384, 768, 3072
A.768
B.384
C.100
D.48
E.12
Answer
Explanation:
Each even term of the series is obtained by multiplying the previous term by 2.
2nd term = (1st term) x 2 = 6 x 2 = 12
4th term = (3rd term) x 2 = 48 x 2 = 96.
6th term = (5th term) x 2 = 384 x 2 =768.
4th term should be 96 instead of 100.
27. Find the wrong number 56, 72, 90, 110, 132, 150
A.72
B.110
C.132
D.150
Answer
Explanation:
The numbers are 7 x 8, 8 x 9, 9 x 10, 10 x 11, 11 x 12, 12 x 13.
So, 150 is wrong.
