Quantitative Aptitude
Quantitative Aptitude
KMAT's quantitative domain tests numerical fluency across arithmetic, algebra, number properties, mensuration and elementary probability. The current paper is typically 120 questions in 120 minutes across four sections, so this domain rewards fast, accurate calculation rather than long derivation. KMAT normally has no negative marking, so a reasoned guess beats a blank.
Core rules and concepts
- Convert common percentages to fractions: 12.5% = 1/8, 16.67% = 1/6, 33.33% = 1/3. This often turns a decimal calculation into cancellation.
- In ratio chains, make the shared term common: if a:b = 2:3 and b:c = 4:5, rewrite as a:b:c = 8:12:15.
- Work rates add. If A alone takes x days and B alone takes y days, together they take xy/(x+y) days.
- Relative speed adds when objects move in opposite directions and subtracts when they move in the same direction.
- SI = PRT/100; CI = P(1 + r/100)^t - P. For two years, CI - SI = P(r/100)^2.
Worked example
A completes a job in 12 days and B in 18. They work together for 4 days, then A leaves. How long does B need to finish the remainder?
Combined rate = 1/12 + 1/18 = 5/36 of the job per day. In 4 days they finish 20/36 = 5/9. Remaining work = 4/9. B's rate is 1/18, so time = (4/9) × 18 = 8 days.
Traps that cost marks
Profit percentage is calculated on cost price, not selling price. Average speed over equal distances is the harmonic mean, not the arithmetic average. Percentage increase and decrease of the same amount do not cancel. Geometry figures are schematic, so do not infer lengths from appearance. Finally, check whether a question asks for the remainder or the total work.