General Aptitude: Data Interpretation, Problem Solving and Logical Reasoning
Data interpretation
Check the axis scale, units and whether a chart shows counts or percentages before computing. Read only the values you need. Distinguish percentage from percentage points: going from 20 percent to 25 percent is a 5 percentage-point rise but a 25 percent relative increase. Percent change = (new - old) / old x 100.
Problem solving
Convert everything into a rate (per hour, per minute, per unit). For work problems, add rates and never times: if A finishes in 6 hours and B in 3 hours, the combined rate is 1/6 + 1/3 = 1/2 job per hour, so they finish in 2 hours. For speed, distance = speed x time, keeping units consistent. In number series, check differences, then ratios, then alternating patterns.
Spatial reasoning
For rotations and mirror images, track one distinctive feature rather than the whole shape. For folded paper or cube questions, count faces and edges systematically so nothing is double-counted.
Verbal and logical reasoning
In analogies, state the relationship in a sentence first. In syllogisms, accept only what is forced: 'All A are B' and 'Some B are C' does not prove anything about A and C. For seating and blood-relation puzzles, draw a quick diagram and fix one anchor point.
Traps to expect
Assuming correlation proves cause; using the wrong base for a percentage; adding times in work problems; reading the wrong axis; treating a 'some' statement as 'all'.
Worked example
Series 2, 6, 12, 20: differences are 4, 6, 8, so the next difference is 10 and the next term is 30.