Which letter pair will come next in the following series?
CU, EX, GA, ID, ?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → KG
The first and second letters of each pair follow separate rules; after Z the count continues from A.
First letters C (3), E (5), G (7), I (9): 2 places ahead each time, so the next is \(9+2=11\), K
Second letters U (21), X (24): 3 places ahead; 3 ahead of X are Y, Z, A, and 3 ahead of A gives D, so the rule is 3 places ahead
The next second letter is 3 ahead of D (4), \(4+3=7\), G
So the next pair is KG.