Family P has a monthly income of ₹40,000 and spends 30 percent of it on food. Family Q has a monthly income of ₹60,000 and spends 25 percent of it on food. Which family spends more on food, and by how much?

Family P spends $0.30\times 40,000$ = ₹12,000 and Family Q spends $0.25\times 60,000$ = ₹15,000, so Family Q spends ₹3,000 more. The bigger percentage belongs to Family P, but percentages of different totals cannot be compared against each other — a smaller share of a larger income is the larger amount here.