Letter and Symbol Series Questions and Answers

Answer: A

Correct answer: Q

The step is four places each time: A(1) to E(5), E to I(9), I to M(13). Four beyond M(13) is position 17, which is Q. Counting positions rather than reciting the alphabet is the quicker check here, because a four-step gap is easy to miscount by one when read aloud. N would be a single step and P a three-step, neither of which matches the pattern already established. A four-step series covers the alphabet in six terms and then wraps, so questions of this shape rarely run long enough for the wrap to be needed.

Answer: B

Correct answer: T

Positions 4, 8, 12, 16 - each four more than the last. The next is position 20, which is T. These are the letters at every fourth place from D, so the run would continue T, X and then wrap. S sits at 19 and U at 21, one either side of the answer; both are tempting if the count is started from the wrong letter, so it is worth fixing the position of P as 16 before adding. Series with a gap of four divide the alphabet into four independent strands, and D, H, L, P, T all belong to the same one.

Answer: C

Correct answer: N

The gap is three places throughout: B(2), E(5), H(8), K(11). Three beyond 11 is position 14, giving N. A useful check is that every term leaves the same remainder on division by three, so the series picks out one letter from each group of three. M at 13 and O at 15 bracket the answer and are the two errors a miscount produces. The three-step gap is the most common in this topic because it produces a long series - nine terms - before the alphabet runs out.

Answer: D

Correct answer: Y

Each letter is five places beyond its predecessor: E(5), J(10), O(15), T(20). Five past 20 is position 25, which is Y. The positions are the multiples of five, which makes the series easy to verify without reciting the alphabet. Z sits at 26 and is the last letter, so it attracts a guess from anyone who assumes the series must finish at the end. Once the positions are written down, a five-step series is just counting in fives, and the only real risk is mistaking the position of the starting letter.

Answer: A

Correct answer: L

The series runs backwards in steps of three: X(24), U(21), R(18), O(15). Three below 15 is position 12, which is L. Working backwards is where most errors creep in, so it helps to convert to positions first and subtract. M at 13 is only two below O and would fit a step of two, which the series has never taken. A useful habit with any descending series is to read it backwards first: L, O, R, U, X climbs by three, which is far easier to confirm than the same series read the other way.

Answer: B

Correct answer: Q

The letters descend two places at a time: Y(25), W(23), U(21), S(19). Two below 19 is position 17, giving Q. The run picks out alternate letters going backwards from Y, so it is the odd-numbered positions in reverse. R at 18 is the immediately preceding letter and is what a single backward step would give. Alternate letters are among the easiest patterns to spot, and the direction is the only thing that has to be settled before answering.

Answer: C

Correct answer: G

Each term is four places back from the one before: W(23), S(19), O(15), K(11). Four below 11 is position 7, which is G. Because the step is large and backwards, converting to positions is far safer than counting letters on the fingers. H at 8 is a three-step and F at 6 a five-step, the two neighbouring errors. Read in reverse the series is G, K, O, S, W, a four-step climb, which is the quickest way to confirm the answer once it has been found.

Answer: D

Correct answer: D

The series falls by four places each time: T(20), P(16), L(12), H(8). Four below 8 is position 4, which is D. The run would end there for practical purposes, since a further four would take it off the front of the alphabet. C at 3 and E at 5 sit either side and are the usual off-by-one answers. Because the step is four and the series has reached position 8, only one more term is possible before the alphabet is exhausted, which is a useful sanity check on the answer.

Answer: A

Correct answer: P

The gaps themselves grow by one each time: A to B is +1, B to D is +2, D to G is +3, G to K is +4. The next gap must be +5, and five beyond K(11) is position 16, which is P. Series of this kind are recognised by the differences rather than by the terms, so writing the gaps underneath is the first move. Assuming a constant gap of four would give O and is the commonest mistake.

Answer: B

Correct answer: Q

The differences increase by one at every step: B to C is +1, C to E is +2, E to H is +3, H to L is +4, so the next must be +5. Five beyond L(12) is position 17, giving Q. Note that the terms are at positions 2, 3, 5, 8, 12, 17 - each is the previous plus the running count. P at 16 would follow from repeating the +4 step instead of increasing it. The running total of the gaps is 1, 3, 6, 10, 15 - the triangular numbers - so the position of the nth term is always the starting position plus a triangular number.