Find the next term in the alphanumeric series:
C5, D16, G24, L72, S48, ?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → B120
Note: The given answer is as per the official NTA Answer Key. However, there seems to be a mistake in the question: the letters lead to B, but the numbers 5, 16, 24, 72, 48 do not follow any one rule that gives 120, as explained below.
In a letter-number series, the letters and the numbers follow separate rules, so each part is checked on its own.
The letters (by their places in the alphabet):
C (3), D (4), G (7), L (12), S (19):
The gaps are +1, +3, +5, +7, the odd numbers in turn
The next gap is +9: \(19+9=28\)
After Z (26) the count starts again from A, so the 28th place is the 2nd letter, B
This rules out D56 (Option 3), but B56, B104 and B120 all begin with B, so the numbers must decide.
The numbers:
5 to 16, 16 to 24, 24 to 72 and 72 to 48 are steps of \(\times3+1\), \(\times1.5\), \(\times3\) and \(\times\frac{2}{3}\), with no common pattern
120 is \(72+48\), the sum of the two numbers before it, but the earlier numbers do not follow that rule (\(24+72=96\), not 48)