# Number Series Logical Reasoning Questions and Answers Part 5

17. What comes next?
A D I P ?

a. V
b. Y
c. A
d. Z

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

Position of A = 1
Position of D = 4
Position of I = 9
Position of P = 16

These are squares of 1, 2, 3, 4
So next has to be square of 5 = 25 = Y

18. What comes in place of question mark?
35Z34, 42U36 , 55P44, 64K48, ?

a. 72F50
b. 84G64
c. 73U36
d. 73F52

Explanation:

Alphabets and their positions and reverse 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 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

Here reverse positions are to be considered.
• 35-34 = 1. A has position 1.
But when reversed Z has position 1.
• 42-36 = 6 ; 6 means 1+5
U has position 6 in reverse
• 55-44 = 11 ; 11 means 6+5
P has position 11 in reverse
• 64-48 = 16 ; 16 means 11+5
K has position 16 in reverse
• Next difference has to be 16+5 = 21
21 is position of F in reverse
Answer is option d where 73-52 = 21

19. A14D   L124X   T206F  ?
Which of the following will fit the above sequence?

a. O301H
b. N224X
c. Z268H
d. U211K

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

See the positions of alphabets
A=1; D=4 ; Middle number is 14
L=12; X=24; Middle Number is 124 (2 is common so written once)
T=20; F = 6=06; Middle Number is 206 (0 is common)

This condition is satisfied by only option d
U=21; K=11; Middle number is 211 (1 is common)

20. PN5, MJ10, IE17, ZU26, ?

a. SM33
b. TN37
c. JG40
d. TL50