Mathematics and Quantitative Aptitude
Mathematics and Quantitative Aptitude tests arithmetic reasoning: percentage, profit and loss, ratio, average, simple interest, time–work, speed–distance, area, and sets. Most items are short, so formula selection and base identification decide the mark.
Core rules
- Percentage change is always on the original base unless stated otherwise.
- Profit% = (SP − CP)/CP × 100; discount% = (MP − SP)/MP × 100.
- Simple interest = P × R × T / 100; amount = P + SI.
- Average = sum of terms / number of terms; average speed = total distance / total time, not the mean of speeds.
Worked example
A trader marks an item 20% above cost and allows a 10% discount. Let CP = 100. MP = 120. SP = 120 − 10% of 120 = 108. Profit = 8, so profit% = 8/100 × 100 = 8%. Reason: the discount is charged on the marked price, not on cost.
Traps
- Adding 20% and subtracting 10% to claim 10% profit.
- Computing discount on CP instead of MP.
- Averaging two speeds directly for a round trip.
- Using the compound-interest formula for a simple-interest question.