ব্যাখ্যা
Question: The monthly incomes of two brothers are in the ratio 11 : 7 and their monthly expenditures are in the ratio 9 : 5. Each of them saves Tk. 4,800 per month. Find the monthly income of the first brother.
Solution:
Let the monthly income of the two brothers are 11x and 7x
Let the monthly expenses of the two brothers are 9y and 5y
Since each saves Tk. 4800 per month.
Then we get,
11x - 9y = 7x - 5y
⇒ 4x = 4y
∴ x = y
Now,
11x - 9y = 4800
⇒ 11x - 9x = 4800
⇒ 2x = 4800
⇒ x = 4800/2
∴ x = 2400
∴ y = 2400
Therefore,
Monthly income of the first brother = 11x = 11 × 2400 = Tk. 26400
So the monthly incomes are Tk. 26400.