Quantitative Aptitude / Numerical Ability
Quantitative Aptitude / Numerical Ability tests calculation speed and the ability to pick the shortest method under time pressure. Expect simplification and approximation, number series, quadratic comparison, data interpretation (table, bar, pie, caselet), and arithmetic on percentage, ratio, average, time-work, speed-distance, interest, profit-loss, and mixtures.
Core rules
- Approximation: round only when options are far apart. If options are close, calculate exactly.
- Number series: test differences, ratios, squares and cubes, and alternating patterns before assuming one rule.
- Successive percentage changes of a% and b% give a net change of a + b + ab/100, with signs.
- Time and work: take total work as the LCM of the given days, then add work rates.
- In data interpretation, note the unit of every axis and total before computing a share.
Worked example
Find the missing term: 3, 7, 16, 35, 74, ? Check the pattern: 3×2+1=7; 7×2+2=16; 16×2+3=35; 35×2+4=74. The number added rises by 1 each step, so the next term is 74×2+5=153.
Traps
Mixing lakh and crore in DI; answering percentage points when the question asks for percentage; treating compound interest as simple interest; and rounding in a way that shifts the answer to a neighbouring option.