Correct Answer - Option 4 : 25
liters
Given:
The ratio of petrol to kerosene = 3 : 5
Quantity of solution replaced with petrol = 16 litres
New ratio of petrol to kerosene = 5 : 3
Calculation:
Let the initial quantity of petrol and kerosene be 3x and 5x
16 litres of solution replaced with petrol
The solution also in the ratio 3 : 5
so petrol in the replaced solution = (3/8) × 16 = 6 litres
Kerosene in the replaced solution = (5/8) × 16 = 10 litres
According to the question
⇒ (3x - 6 + 16)/(5x - 10) = 5/3
⇒ (3x + 10)/(5x - 10) = 5/3
⇒ 3(3x + 10) = 5(5x - 10)
⇒ 9x + 30 = 25x - 50
⇒16x = 80
⇒ x = 5
The original amount of kerosene = 5x = 25 litres
∴ The original amount of kerosene in the solution is 25 litres