Explanation:

To find the correct ratio, let's calculate:

- Selling price of the mixture = Rs 60 per litre

- Desired profit = 50%

Steps:

- Calculate the cost price for 50% profit:

- Selling Price = Cost Price + Profit

- Profit = 50% of Cost Price

- Selling Price = 1.5 * Cost Price

- \(\text{Cost Price} = \frac{\text{Selling Price}}{1.5} = \frac{60}{1.5} = 40\)

- Let the ratio of kerosene to spirit be \(x:y\).

- Cost price of mixture = 40 = \(\frac{48x + 30y}{x + y}\)

- \(40(x + y) = 48x + 30y\)

- Simplifying, we have: \(40x + 40y = 48x + 30y\)

- \(8x = 10y\)

- \(\frac{x}{y} = \frac{5}{4}\)

Options:

1. 1:1: This implies equal parts of each, which doesn't satisfy the equation.

2. 5:4: ?? Correct Answer: This ratio holds true to the cost calculation.

3. 2:3: This doesn't balance the derived equation.

4. 3:4: This ratio doesn't meet the cost criteria for 50% profit.

Therefore, Option 2 (5:4) is correct.