BPSC 70th CCE Prelims General Studies · Question 44 of 143

Correct — A, PSVX. Convert every letter to its position in the alphabet and the question answers itself. Option (b) ORUX is O = 15, R = 18, U = 21, X = 24, so the steps are +3, +3, +3. Option (c) JMPS is J = 10, M = 13, P = 16, S = 19 — again +3, +3, +3. Option (d) CFIL is C = 3, F = 6, I = 9, L = 12 — +3, +3, +3 once more. Option (a) PSVX is P = 16, S = 19, V = 22, X = 24, and its steps are +3, +3, +2. The final jump is one letter short: to hold the pattern the group would have had to end at Y, position 25, giving PSVY. That broken step is the only property that isolates exactly one of the four groups, which is what an odd-one-out question requires, so PSVX is the odd group. The same conclusion falls out of a faster check worth keeping as a habit: measure the span from the first letter to the last and skip the intermediate arithmetic altogether. ORUX spans 24 − 15 = 9, JMPS spans 19 − 10 = 9, CFIL spans 12 − 3 = 9, and PSVX spans 24 − 16 = 8. One span differs from the other three and you are done in four subtractions. It is equally important to see what does not separate them, because discarding a candidate classifier is the real work in this item type. Vowel content splits the set unevenly rather than three against one — ORUX carries two vowels, CFIL one, and JMPS and PSVX none. No group forms a word, no group repeats a letter, and all four begin with a consonant. Only the step size gives a 3–1 split, and it points at PSVX.

• (b)ORUX — A clean arithmetic chain: O = 15, R = 18, U = 21, X = 24, stepping +3 each time and spanning 9. It shares its final letter X with PSVX, which is the deliberate distraction — the shared endpoint tempts you to compare these two groups against each other rather than testing all four by the same rule.
• (c)JMPS — J = 10, M = 13, P = 16, S = 19: +3, +3, +3, span 9. It is the group most people convert last because its letters sit in the middle of the alphabet and are the hardest to place by eye, but it follows exactly the same rule as ORUX and CFIL and so cannot be the odd one.
• (d)CFIL — C = 3, F = 6, I = 9, L = 12 — the easiest chain to verify, since its positions are simply the first four multiples of three, and again +3, +3, +3 with a span of 9. Starting at the front of the alphabet makes it look unlike the others superficially, but position of the starting letter is not a property the question is testing.

Every letter-group question rests on one move: replace each letter by its position in the alphabet, so that a pattern in symbols becomes arithmetic you can actually compute. A = 1 through Z = 26, and the EJOTY mnemonic fixes five anchors — E = 5, J = 10, O = 15, T = 20, Y = 25 — so any letter is at most two counts away from a number you already know. Once the groups are numbers, only a handful of patterns ever appear in this exam. A constant step, as here. Alternating steps, such as +6, +3, +2 repeated across every group. Complementary or mirror letters, where a letter and its opposite from the far end of the alphabet sum to 27 (A + Z, B + Y, C + X and so on). Skip patterns that count forward through consonants only, or through the alphabet in reverse. In an odd-one-out item you are not asked to name the pattern the setter had in mind; you are asked to find a single test under which exactly one group behaves differently, which means a valid classifier must produce a 3–1 split and nothing else will do.

Work these to a fixed procedure rather than by inspiration. Convert all four groups to numbers first, before forming any opinion — the commonest way to lose this mark is to spot a pattern in two groups, assume it, and never check the fourth. Then compute the first-to-last span for each group, because a difference in span exposes a broken step in one subtraction instead of three. If the spans are equal, drop to the individual gaps. If the gaps match too, move to a second classifier: the mirror test (does each group's letters pair to 27 with a fixed partner?), the vowel count, whether the letters spell anything, whether any letter repeats. Discard each classifier the moment it fails to give a 3–1 split, and never keep one that splits the set two against two — a 2–2 classifier cannot answer this question no matter how elegant it looks. Here the very first test succeeds: three spans of 9 and one of 8. Note also that BPSC has now set this exact item type in consecutive cycles, which makes the procedure worth more than the specific answer.

• A = 1 through Z = 26; the EJOTY mnemonic fixes E = 5, J = 10, O = 15, T = 20, Y = 25, from which any other letter is a short count away
• The four groups as positions: PSVX = 16, 19, 22, 24; ORUX = 15, 18, 21, 24; JMPS = 10, 13, 16, 19; CFIL = 3, 6, 9, 12
• Step patterns: +3, +3, +2 for PSVX against +3, +3, +3 for each of the other three — equivalently a first-to-last span of 8 against three spans of 9
• Had the pattern held, the group would have run P, S, V, Y, ending at position 25 instead of 24
• Mirror or complementary letters sum to 27 — A + Z, B + Y, C + X — which is the second classifier always worth testing on letter groups, though it yields no split in this set

• Deciding the pattern from two groups and never converting the remaining two
• Keeping a classifier that splits the set two against two; only a 3–1 split can answer an odd-one-out question
• Miscounting positions near the end of the alphabet, where V, W, X and Y are easy to slip by one — anchor on Y = 25 and count back

BPSC sets pure reasoning items like this one alongside its general studies questions in the same paper, usually with no hint of the criterion in the stem, so choosing the classifier is the whole task. The 69th CCE asked the identical type with a +6, +3, +2 pattern instead of a constant +3. UPSC does not set letter groups in General Studies Paper I at all; the equivalent skill is examined in the qualifying CSAT paper, where it appears as series completion, coding-decoding and analogy.

• practice — not a real PYQ

  Choose the group of letters which is different from the others.

  • (a)DGJM
  • (b)FILO
  • (c)HKNQ
  • (d)MPSU

  Answer(d) MPSU — 13, 16, 19, 21 steps +3, +3, +2, while DGJM (4, 7, 10, 13), FILO (6, 9, 12, 15) and HKNQ (8, 11, 14, 17) all step by a constant +3.

• practice — not a real PYQ

  Which letter should come next in the series C, F, I, L, __ ?

  • (a)N
  • (b)O
  • (c)P
  • (d)Q

  Answer(b) O — the positions are 3, 6, 9, 12, so the next term is 15, which is O.