Which option will replace the question mark in the given series:
BB0, EC2, HE3, KG4, NK3, ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → QM4
In a letter-number series, each part of the term follows its own rule, so the first letters, the second letters and the numbers are checked separately.
First letters B (2), E (5), H (8), K (11), N (14): each is 3 places ahead, so the next is Q (17)
Second letters B (2), C (3), E (5), G (7), K (11): their positions are the prime numbers in order, so the next is the 13th letter, M
Each number is the first letter’s position minus the second letter’s: \(2-2=0\), \(5-3=2\), \(8-5=3\), \(11-7=4\), \(14-11=3\)
For the missing term: \(17-13=4\), so the term is QM4