MAT Exam 2022 Paper

Concept:When price and consumption both change by percentages, multiply the original bill by the corresponding decimal factors.Explanation:Price increases by $10\%$, so the price factor becomes $1 + 0.10 = 1.10$. Consumption decreases by $10\%$, so the consumption factor becomes $1 - 0.10 = 0.90$. New bill $= 200 \times 1.10 \times 0.90$. First, $200 \times 1.10 = 220$. Then, $220 \times 0.90 = 198$. So the net change gives a bill lower than Rs. 200.Answer:The petrol bill in August is Rs. 198, i.e., Option D.