MAT Exam 2020 Paper

Concept:Profit percentage depends on the relationship between total earnings and total expenses for a trip.Explanation:Let each passenger pay ₹ $a$ for one trip.Let the auto-rickshaw consume $b$ litres of petrol per trip.Initially, petrol price is ₹ 30 per litre.Total expense $= 30b$Total earning $= 3a$Given profit is 20%, so:$3a - 30b = 20\% \text{ of } 30b$$3a - 30b = \frac{20}{100} \times 30b = 6b$$3a = 36b$Hence, $a = 12b$Now, petrol price reduces to ₹ 24 per litre and there are 4 passengers.New total expense $= 24b$New total earning $= 4a = 4(12b) = 48b$Profit $= 48b - 24b = 24b$Profit percentage:$\frac{\text{Profit}}{\text{Expense}} \times 100 = \frac{24b}{24b} \times 100 = 100\%$Answer:100% (Option C)