7 8 16 43 ?
a. 107
b. 96
c. 86
d. 103
Answer: a. 107
Explanation:
8 - 7 = 1
16 - 8 = 8
43 -16 = 27
1, 8, 27 are cubes of 1, 2 and 3
So next difference must be cube of 4
So, ? - 43 = 43 = 64
So, ? = 64+43 = 107
14. 20, 4, 24, 64, 30, 196, 38, ?
a. 361
b. 400
c. 420
d. 441
Answer: b. 400
Explanation:
Here we see ups and downs in the series so there is a chance of 2 separate series
We can have 20 24 30 38 as one series
And 4 64 196 as other series.
Both series occur alternately so next term has to be of the second series.
In first series difference is
24 - 20 = 4
30 - 24 = 6
38 - 30 = 8
So, difference increases by 2
In second series, We see they are squares i.e. 22, 82, 142
8-2 = 6
14-8 = 6
So next number, ? - 14 has to be = 6
So, ? = 14+6 = 20
So next term is 202 = 400
15. CZ , HU, NQ, ?
a. VN
b. UN
c. TM
d. VO
Answer: a. VN
Explanation:
Alphabet Series - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Here the first letters of the terms is C, H, N
H is 5th letter from C
N is 6th letter from H
So next has to be 7th letter from N i.e. V
In the second letters we have Z, U, Q
U is 5th letter from Z
Q is 4th letter from U
So next has to be 3rd letter from Q i.e. N
16. What is the next term?
AN13 , BZ24 , CO12 , DY21 , ?
a. EP18
b. EX18
c. FX10
d. EP11
Answer: d. EP11
Explanation:
Alphabets and their positions
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 |
- First letters of each term are A, B, C, D. So, in answer first letter should be E.
- Second letters are N, Z, O, Y. We can observe there are alternately 2 series N, O, etc. and Z, Y, etc.
- So next has to be P which comes after O.
- In many alphanumeric series, numbers are mostly related to the positions of the letters.
- See the first term, A has position 1. N has position 14. 14 -1 = 13
- Similarly, B has position 2. Z has 26. 26 - 2 = 24
- In ? we have EP. E has position 5. P has 16. 16 - 5 = 11


