The ratio of income and expenditure of a person is 7 : 5, If he saves Tk. 9000 per annum, what is his monthly income?

Question: The ratio of income and expenditure of a person is 7 : 5, If he saves Tk. 9000 per annum, what is his monthly income?

Solution:
Let, income = 7x
and expenditure = 5x
Then,
7x - 5x = 9000
⇒ 2x = 9000
∴ x = 4500

Annual income = 7x = 7 × 4500 = Tk. 31500
Monthly income = 31500/12 = Tk. 2625