Percentage to Fraction

Cooking and recipes are the most common everyday context. A North Indian sweet recipe calling for "25% sugar by weight of flour" means add ¼ kg of sugar per 1 kg of flour — same number, easier to measure on a kitchen scale. SSC and bank-exam quant sections frequently test the reverse: "a discount of 12.5% means deducting what fraction of the marked price?" (Answer: 1/8.)

The trick to fast conversion is memorising the standard fractions: 50% = ½, 25% = ¼, 20% = 1/5, 12.5% = 1/8, 10% = 1/10, 6.25% = 1/16, 33⅓% = 1/3, 16⅔% = 1/6, 14²⁄₇% = 1/7. Most quantitative aptitude questions in Indian competitive exams reduce to one of these.