The incomes of M and N are in the ratio 5 : 4 and their expenditures are in the ratio 4 : 3. If each of them saves Rs 1,800, what are the incomes of M and N respectively?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Rs 9,000 and Rs 7,200
Income − expenditure = saving for each person; the equal savings give two equations.
Incomes \(5x,\ 4x\); expenditures \(4y,\ 3y\)
\(5x-4y=1800\) and \(4x-3y=1800\)
Subtracting: \(x-y=0\), so \(y=x\)
\(5x-4x=1800\), so \(x=1800\)
Incomes \(=5\times1800=\) Rs 9,000 and \(4\times1800=\) Rs 7,200
Check: expenditures Rs 7,200 and Rs 5,400 (ratio 4 : 3), savings Rs 1,800 each
Their incomes are Rs 9,000 and Rs 7,200.