Letter and Symbol Series Questions and Answers

Answer: C

Correct answer: N

The series falls, alternating -2 and -3: Z(26), X(24), U(21), S(19), P(16). The next step is -2, giving position 14, which is N. Backwards alternating gaps are the most error-prone of these constructions, and converting every term to its position before subtracting is the only reliable method. O at 15 is a single backward step. Descending alternating gaps are the most error-prone construction in this topic, and converting every term to its position before subtracting is the only dependable method.

Answer: D

Correct answer: Q

The gaps alternate between two and three: E(5), G(7), J(10), L(12), O(15). The next gap is +2, so the series reaches position 17, which is Q. Every second term advances five places, so the terms at the odd positions are E, J and O - a five-step series in its own right, which is a neat check on the working. The odd-position terms E, J and O climb by five, which confirms the reading without re-examining every gap.

Answer: A

Correct answer: R

The differences run +2, +3, +2, +3 from F(6): H(8), K(11), M(13), P(16). The next difference is +2, giving position 18, which is R. As with the others of this family the alternation must be established from at least three gaps before it can be trusted, since two gaps alone are consistent with several rules. Establishing an alternation needs at least three gaps, since two are consistent with several different rules and give no way to choose between them.

Answer: B

Correct answer: V22

Each term pairs a letter with its position counted from the start of the alphabet: Z is the 26th letter, Y the 25th, X the 24th, W the 23rd. The next letter down is V, the 22nd, so the term is V22. The two halves are not independent series - the number simply restates the letter - so getting one right guarantees the other. The number is not an independent strand but a restatement of the letter, so an option whose number does not match its letter's position can be rejected immediately.

Answer: C

Correct answer: IJ

The alphabet is being taken in consecutive pairs: A and B, then C and D, then E and F, then G and H. The next two letters are I and J, giving IJ. Nothing is skipped, which distinguishes this from the pairs that start three or four places apart. HI begins one letter too early, which happens if the pairs are allowed to overlap. Consecutive pairs use the alphabet without gaps, so thirteen pairs exhaust it exactly - and IJ is the fifth of those thirteen.

Answer: D

Correct answer: J10

The letters advance two places at a time - B, D, F, H - and each is paired with its own position in the alphabet: B is 2nd, D is 4th, F is 6th, H is 8th. The next letter is J, the 10th, giving J10. Because the number restates the letter, the pairing itself is a built-in check on the answer. Every letter used sits at an even position, and its number simply restates that position, so the two halves of each term check one another.

Answer: A

Correct answer: Q17

Each term is a letter with its alphabet position, and the letters descend two places at a time: Y(25), W(23), U(21), S(19). The next letter is Q at position 17, so the term is Q17. The numbers falling by two follows automatically from the letters, so there is only one series here despite the appearance of two. Because the number restates the letter's position, only one of the four options can be internally consistent, which narrows the field before the pattern is even considered.

Answer: B

Correct answer: E5

The letters step back two places at a time - M, K, I, G - and each carries its own alphabet position. The next letter is E, the 5th, giving E5. Checking that the number matches the letter's position is the quickest way to eliminate wrong options: E7 pairs a letter with a position that is not its own. The series is descending, so it will reach the front of the alphabet after two more terms, at C3 and A1.

Answer: C

Correct answer: E4

The letters advance one place at a time while the numbers are halved at each step: 64, 32, 16, 8. Half of 8 is 4, so the term is E4. Halving series are read most easily from the right-hand end, where the numbers are small and the relationship is obvious. E6 comes from subtracting a constant, which fits no pair in the series. Halving series are read most easily from the small end, where 8, 4 and 2 make the relationship plain even if the larger terms do not.

Answer: D

Correct answer: T81

The letters advance one place at a time - P, Q, R, S - while the numbers are multiplied by three: 1, 3, 9, 27. Three times 27 is 81, so the term is T81. T54 comes from doubling and adding, a rule that fits no adjacent pair here; checking a candidate against the first pair as well as the last is what exposes it. Powers of three grow quickly, and writing them as 3 to the power 0, 1, 2 and 3 makes the next term immediate without repeated multiplication.