General Mathematics / Arithmetic
What is tested
General Mathematics / Arithmetic tests numerical accuracy under time pressure. Prepare percentages, ratio and proportion, averages, profit and loss, simple and compound interest, time and work, speed and distance, mensuration, and data interpretation. Most questions are one- or two-step problems, so formula recall and careful unit conversion matter more than long calculation.
Core formulas
- Profit percent = (SP - CP) / CP x 100; loss percent uses CP as the base.
- Discount is calculated on marked price, not on cost price.
- Simple interest = P x R x T / 100; compound amount = P(1 + R/100)^T.
- Average = sum of values / number of values.
- Work: if A finishes in x days and B in y days, together they finish in xy/(x + y) days.
- Speed = distance / time; convert km/h to m/s by multiplying by 5/18.
Worked example
A shopkeeper marks an article 25% above cost and gives a 10% discount. Find the profit percent. Let CP = 100. Marked price = 125. Selling price = 125 x 0.90 = 112.50. Profit = 12.50 on CP 100, so profit percent = 12.5%. The reasoning matters: the discount is on MP, while profit is on CP. A common wrong method is 25% - 10% = 15%.
Traps that cost marks
Do not add or subtract percentage changes directly unless the base is the same. Check whether the question asks for profit percent or profit amount. In time and work, do not add days; add one-day work rates. In interest, confirm whether interest is simple or compounded and whether time is in months.