Mental Ability: pattern recognition over calculation
Mental Ability supplies 50 of PTET's 200 one-mark questions and tests spotting a rule quickly, not long computation. Items recycle a small set of formats: number and letter series, analogies, odd-one-out classification, coding–decoding, direction sense, blood relations, ranking, syllogism/Venn diagrams, and arithmetic reasoning (percentage, ratio, average, time–work, speed–distance, ages).
Rules that generate most items
- Series: test successive differences first, then ratios, then squares/cubes or near-misses (n² ± 1). If none fit, check two interleaved series (odd positions, even positions) or a digit-wise operation.
- Letters: fix A = 1 … Z = 26 and memorise EJOTY (E = 5, J = 10, O = 15, T = 20, Y = 25). Reverse position = 27 − forward position.
- Coding: align the coded word against the plain word letter by letter; look for a constant shift, reversal, or position-sum before guessing.
- Direction: draw the axes and mark every turn. Unless the question asks for distance walked, the answer is displacement from the start.
- Blood relations: draw a tree with gender markers; never solve it mentally.
Worked example
Series: 3, 7, 16, 35, 74, ? Step 1 - differences: 4, 9, 19, 39. Not constant, so difference series is not the rule. Step 2 - try ×2 + k: 3×2+1 = 7, 7×2+2 = 16, 16×2+3 = 35, 35×2+4 = 74. The added number rises by one each time. Step 3 - next term: 74×2+5 = 153. Options like 148 (plain ×2) and 149 (×2+1) are the standard distractors, so verify the increment, not just the doubling.
Traps
- No negative marking means a blank is a wasted mark; never leave an item unattempted.
- Direction questions assume the person faces north unless a turn is stated.
- In syllogism, accept only what the premises force; real-world truth is irrelevant.
- A tempting single-step answer is usually a distractor in two-step arithmetic items.
- Unit mismatches (metres vs km, minutes vs hours) cause silent errors.