Find the next term in the alphanumeric series:
Z3, B8, F24, L48, T120, ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → D168
In an alphanumeric series the letters and the numbers follow separate rules, so each part is worked out on its own.
The letters (by their place in the alphabet, counting on from Z back to A):
Z (26) to B (2): +2
B (2) to F (6): +4
F (6) to L (12): +6
L (12) to T (20): +8
Next: T (20) + 10 \(=30\), which is 4 places past Z, so D
The numbers are each one less than the square of a prime, the primes in order:
\(3=2^2-1\), \(8=3^2-1\), \(24=5^2-1\)
\(48=7^2-1\), \(120=11^2-1\)
Next prime 13: \(13^2-1=168\)
The next term is D168.