The monthly incomes of A and B are in the ratio of 5 : 4 and their mon

1.	The monthly incomes of A and B are in the ratio of 5 : 4 and their monthly expenditures are in the ratio of 7 : 5. If each saves Rs. 9000 per month, find the monthly income of each.
Answer» Let the monthly income of A and B are Rs.x and Rs.y respectively. Then as per the question x/y = 5/4 ⇒ y = 4x/5 Since each save Rs.9,000, so Expenditure of A = Rs.(x – 9000) Expenditure of B = Rs.(y – 9000) The ratio of expenditures of A and B are in the ratio 7:5. ∴ x−9000/y−9000 = 7/5 ⇒7y – 63000 = 5x – 45000 ⇒7y – 5x = 18000 From (i), substitute y = 4x/5 in (ii) to get 7 × 4x/5 – 5x = 18000 ⇒28x – 25x = 90000 ⇒3x = 90000 ⇒x = 30000 Now, putting x = 30000, we get y = 4×30000/5 = 4 × 6000 = 24000 Hence, the monthly incomes of A and B are Rs. 30,000 and Rs.24,000.

The monthly incomes of A and B are in the ratio of 5 : 4 and their monthly expenditures are in the ratio of 7 : 5. If each saves Rs. 9000 per month, find the monthly income of each.

Answer»

Let the monthly income of A and B are Rs.x and Rs.y respectively.

Then as per the question

x/y = 5/4

⇒ y = 4x/5

Since each save Rs.9,000, so

Expenditure of A = Rs.(x – 9000)

Expenditure of B = Rs.(y – 9000)

The ratio of expenditures of A and B are in the ratio 7:5.

∴ x−9000/y−9000 = 7/5

⇒7y – 63000 = 5x – 45000

⇒7y – 5x = 18000

From (i), substitute y = 4x/5 in (ii) to get

7 × 4x/5 – 5x = 18000

⇒28x – 25x = 90000

⇒3x = 90000

⇒x = 30000

Now, putting x = 30000, we get

y = 4×30000/5 = 4 × 6000 = 24000

Hence, the monthly incomes of A and B are Rs. 30,000 and Rs.24,000.