Letter and Symbol Series Questions and Answers

Answer: C

Correct answer: QS

Within each pair the two letters are two places apart - A to C, E to G - and the pairs themselves start four places apart: A, E, I, M. The next pair starts at Q and so is QS. Both the internal gap and the gap between pairs have to be read; getting one right and the other wrong produces QR, which keeps the correct start but loses the internal spacing. With pairs two apart internally and four apart between pairs, the series consumes the alphabet in blocks of four and reaches its end after six pairs.

Answer: D

Correct answer: RT

Each pair holds two letters two places apart, and successive pairs begin four places apart: B, F, J, N. The next begins at R, giving RT. Writing the starting letters alone - B, F, J, N, R - makes the outer pattern obvious and reduces the problem to reproducing the internal gap. RS narrows that gap to one and is the usual error. Every letter used lies at an even position, so the whole series is drawn from the same half of the alphabet, which is a useful check on any candidate answer.

Answer: A

Correct answer: LM

Each pair is two consecutive letters and the pairs move backwards three places at a time: X, U, R, O. The next pair begins at L and so is LM. Working backwards while also holding the internal structure is what makes this harder than its forward equivalent; taking the first letters alone and stepping down in threes is the reliable route. KL starts one place too far back. Reading the series backwards gives LM, OP, RS, UV, XY - a forward three-step - which is the easier direction in which to confirm it.

Answer: B

Correct answer: II

Each term is a letter doubled, and the letters advance two places at a time: A, C, E, G. The next letter is I, so the term is II. The doubling is decoration; the whole of the pattern lives in the single underlying letter series. HH follows the letters one place at a time and ignores the two-step that the series has used throughout. Doubling a letter is a common decoration in this topic and never carries the pattern; the rule always lies in the underlying single letter.

Answer: C

Correct answer: V

The terms alternate between the two ends of the alphabet. The odd-position terms run A, C, E, climbing two at a time; the even-position terms run Z, X, falling two at a time. The next belongs to the descending strand, and two below X(24) is position 22, which is V. W at 23 is a single backward step and is what a reader who has not separated the strands will choose. The two strands converge on the middle of the alphabet, so the series can run for at most thirteen terms before they meet.

Answer: D

Correct answer: S

Each pair of adjacent terms sums to 27 in alphabet position: B(2) with Y(25), E(5) with V(22), and so H(8) must pair with position 19, which is S. Read as two strands the same thing appears - B, E, H climbing by three and Y, V falling by three. The complement-to-27 relationship is the faster check because it needs no memory of the earlier terms. The complement rule and the two-strand reading are the same fact seen from different directions, and either can be used to check the other.

Answer: A

Correct answer: S

The terms pair off to a constant sum: D(4) and W(23) make 27, F(6) and U(21) make 27, so H(8) must be followed by position 19, which is S. Equivalently, the odd-position terms climb by two and the even-position terms fall by two. Both readings give the same answer, and agreement between two methods is the best check available on a series question. Because each adjacent pair sums to 27, the answer can be found from the immediately preceding term alone, without reconstructing the whole series.

Answer: B

Correct answer: N

Each adjacent pair sums to 27: G(7) with T(20), J(10) with Q(17), so M(13) pairs with position 14, which is N. This is the hardest of the complement series because the two strands have converged almost to the middle of the alphabet, so the terms no longer look far apart and the pattern is easy to miss. Reading the strands separately gives G, J, M climbing by three and T, Q falling by three, which points to the same answer.

Answer: C

Correct answer: $

These are the shifted characters of the number row, taken in reverse: shift-8 gives *, shift-7 gives &, shift-6 gives ^, shift-5 gives %. Continuing backwards, shift-4 gives $. Symbol series almost always depend on keyboard order rather than on any mathematical rule, so the keyboard is the thing to picture. # is shift-3 and would be the term after next. Symbol series depend on the physical keyboard rather than on any ordering intrinsic to the characters, so the row of number keys is what should be pictured.

Answer: D

Correct answer: }

The series steps through the bracket pairs in the order they appear on the keyboard, giving each opening bracket followed by its closing partner: round, then square, then curly. The curly pair has been opened but not closed, so the next symbol is }. Recognising that the terms come in pairs is the whole of the problem; the individual symbols carry no arithmetic. There are only three bracket pairs in common use, so a series of this kind can run for at most six terms before it must repeat or stop.