Letter and Symbol Series Questions and Answers

Answer: C

Correct answer: L

The positions double each time, wrapping when they pass 26. D is 4, H is 8, P is 16, then 32 wraps to 6, which is F. Doubling 32 gives 64, and subtracting 26 twice leaves 12, which is L. The series has already wrapped once before the question mark, which is the clue that the rule involves wrapping at all - without it the fourth term could not be F. The wrap before the question mark is the clue that the alphabet is being treated as a loop; without it the fourth term could not be F.

Answer: D

Correct answer: JI

Each pair is two consecutive letters written in reverse, and the pairs advance two places at a time: BA, DC, FE, HG. The next pair takes J and I, giving JI. The reversal is easy to lose when writing the answer, which is why IJ - the right letters in the wrong order - is the most attractive distractor. The reversal is easy to lose when writing the answer down, which is why the same two letters in the wrong order are always among the options.

Answer: A

Correct answer: RQ

The pairs run backwards through the alphabet, two letters at a time, with each pair written in descending order: Z and Y, then X and W, then V and U, then T and S. The next pair is R and Q, giving RQ. Both the direction of the series and the order within each pair are descending, and keeping the two consistent is where the errors arise. Everything descends here, both within each pair and between pairs, so listing the leading letters Z, X, V, T and R first is the safest route.

Answer: B

Correct answer: LKJ

Each group is three consecutive letters written in reverse, and the groups step forward three places at a time: the highest letters are C, F, I. The next group is built on L, so it reads LKJ. Reading the groups by their first letter - C, F, I, L - reduces the problem to a simple three-step series. JKL has the right letters but restores them to ascending order. Reading the groups by their highest letter reduces the problem to the three-step series C, F, I, L, after which the reversal is mechanical.

Answer: C

Correct answer: NML

Each group holds three consecutive letters in descending order, and successive groups begin three places further on: E, H, K. The next begins at N and reads NML. The two rules - the internal reversal and the three-step between groups - are independent, and the answer has to honour both. MLK starts one place too early. The internal reversal and the three-step between groups are independent rules, and an answer must satisfy both to be correct.

Answer: D

Correct answer: IHG

Each group is three consecutive letters in descending order, and the groups themselves move backwards three places at a time: they begin at R, O, L. The next begins at I and reads IHG. Everything in this series descends, both within the groups and between them, which makes it easy to lose a step; listing the leading letters R, O, L, I first is the safest route. Listing the leading letters R, O, L and I first separates the two descending motions and makes the answer straightforward.

Answer: A

Correct answer: 10J

Each term pairs an even number with the letter at that position in the alphabet: 2 with B, 4 with D, 6 with F, 8 with H. The next even number is 10 and the tenth letter is J, so the term is 10J. Because the letter is fixed by the number, the two halves cannot be counted independently - which is exactly what 10I gets wrong. Because the letter is fixed by the number, the two halves cannot be counted independently, and an inconsistent pairing can be rejected on sight.

Answer: B

Correct answer: 15O

The numbers are the multiples of three - 3, 6, 9, 12 - and each letter sits at that position in the alphabet: C is 3rd, F is 6th, I is 9th, L is 12th. The next multiple is 15 and the 15th letter is O, giving 15O. The pairing makes the answer self-checking: count fifteen letters and confirm it is O before writing it down. The pairing is self-checking: counting fifteen letters into the alphabet confirms O before the answer is committed to.

Answer: C

Correct answer: 25Y

The numbers climb in fives and each letter stands at the matching alphabet position: 5 is E, 10 is J, 15 is O, 20 is T. The next number is 25 and the 25th letter is Y, giving 25Y. The series stops naturally here, since a further five would pass the end of the alphabet. 25X pairs the right number with the letter one place short. The series stops naturally at 25, since a further five would carry it past the end of the alphabet with no letter to pair.

Answer: D

Correct answer: 20T

The numbers are the multiples of four and each letter occupies that position in the alphabet: 4 is D, 8 is H, 12 is L, 16 is P. The next multiple is 20 and the 20th letter is T, so the term is 20T. Because each half determines the other, an answer can be checked without reference to the earlier terms at all. Each half of the term determines the other, so an answer can be verified without reference to any of the earlier terms.