Select the term from among the given options that can replace the question mark (?) in the following series. PJ 16, SM 25, VP 36, YS 49, ?

Correct — C. Split each term into its two letters and its number, and run three separate series.

Rule: first letter +3, second letter +3, number = consecutive squares.

First letters: P(16), S(19), V(22), Y(25), then B, since 25 + 3 = 28 and 28 wraps to B.
Second letters: J(10), M(13), P(16), S(19), then V(22).
Numbers: 16, 25, 36, 49 are 4², 5², 6², 7², so the next is 8² = 64.

Put the three together and the term is BV 64, option (c).

Why the others are wrong

• (a)
  DW 64 — DW 64 has the right number. Its first letter moves five places from Y and its second four places from S, where this series moves each letter three.
• (b)
  CW 81 — CW 81 moves both letters four places instead of three, and it jumps to 9² = 81, skipping 8² = 64.
• (d)
  CV 36 — CV 36 gets the second letter right but moves the first four places to C instead of three to B, and 36 has already been used as the third term's number.

An alphanumeric series is several series printed side by side. Separate them before you look for a pattern in any one of them.

Here both letters advance by three places every term, and once you pass Z you carry on from A: Y + 3 lands on B.

The numbers are not a plain difference series. The gaps run 9, 11, 13, which is the signature of consecutive squares — 4², 5², 6², 7² — so the next number is 8² = 64.

Key facts

• P, S, V, Y, B is a +3 step through the alphabet, wrapping from Z back to A.
• J, M, P, S, V is the same +3 step.
• 16, 25, 36, 49 and 64 are the squares of 4, 5, 6, 7 and 8.

Common traps

• Counting the step inclusively, taking Y itself as the first move and landing on A.
• Choosing DW 64 because the number is right, without checking that each letter moved three places.
• Choosing CV 36 because V is correct, when 36 has already appeared at the third term.

No directly related past PYQ was found.