Question

The monthly income of A and B are in the ratio of 9:7. And their monthly expenditure is in the ratio 4:3. If each saves Rs 1600

per month, find the monthly income of each. Who is more economical? What value of his is depicted here?

Answer 1

Income ratio: 9:7=== 9X, 7X
Expense ratio = 4:3=== 4Y, 3Y
Given each saves 1600, that is their savings are equal
Income - Expense = savings
9X - 4Y = 1600...(i)
7X - 3Y = 1600....(ii)
Savings equal, hence:
9X - 4Y = 7X - 3Y
2X = Y
Sub for Y in eq(i)
9X - 4*2X = 1600
X = 1600
Income of A = 9X = 9*1600 = 14,400
Income of B = 7X = 7*1600 = 11,200
B is more economical since he spends less compared to A (can be understood from their expenditure ratio 4:3)
Hope it helps.