Letter and Symbol Series Questions and Answers

Answer: C

Correct answer: 9i

The numbers count up in odds - 1, 3, 5, 7, then 9 - and the letters keep step with them, A being the 1st letter, C the 3rd, E the 5th and G the 7th. The 9th letter is I, so the term is 9I.

Answer: D

Correct answer: J

Every letter is two places further on than the one before it: B to D, D to F, F to H. Two places past H is J. The series is simply the even-numbered letters of the alphabet - positions 2, 4, 6, 8, 10. The trap is I, which is the very next letter but only one step on; the gap here has been two throughout and there is nothing in the series to suggest it changes. Series built on a single constant gap are the foundation of this topic, and every harder pattern here is a variation on one: alternating gaps, growing gaps, or two such series interleaved.

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.