Reasoning and Quantitative Aptitude
What is tested
Reasoning and Quantitative Aptitude tests speed with accuracy: arithmetic, data interpretation, series, syllogisms, puzzles, seating and coding. The IIFCL paper favours caselet-style calculation and structured puzzles, so write down the given data before computing.
Quant rules
- Percentage change = (new − old)/old × 100; percentage points are absolute differences, not relative changes.
- Simple interest: SI = P × R × T/100; compound interest: A = P(1 + R/100)^T. For the same rate, CI exceeds SI after the first year.
- Time and work: if A finishes in x days, one day's work is 1/x; combine rates only for simultaneous work.
- Average speed for equal distances is harmonic: 2xy/(x+y), not (x+y)/2.
- In DI, check units (lakh/crore, tonnes/kg) and whether the question asks for share or absolute value.
Reasoning rules
In syllogism, draw minimal Venn diagrams and accept only conclusions true in every diagram. In linear seating, fix left/right from the facing direction. In puzzles, convert clues into a table; do not guess.
Worked example
A sum doubles in 8 years under simple interest. Find the rate. Double means interest = P. So P = P × R × 8/100; cancel P: 1 = 8R/100; R = 12.5% per annum. If the question said 'compound interest', the answer would be higher because interest earns interest.
Traps
Mixing SI and CI, using average of speeds for equal distances, ignoring 'approximately', and over-reading 'some' in syllogisms are common. In DI, a percentage increase from 20 to 25 is 25%, not 5%.