Explanation:

- We know two numbers have a product of 2160 and an HCF of 12.

- True numbers can be represented as 12x and 12y, where HCF is common.

- Therefore, 144xy (12x * 12y) equals 2160. Simplifies to xy = 15.

- Also, the sum of squares (12x)^2 + (12y)^2 equals 4896.

- Simplifying: 144(x^2 + y^2) = 4896; therefore, x^2 + y^2 = 34.

- Use identity: (x + y)^2 = x^2 + y^2 + 2xy; gives us (x + y)^2 = 64.

- Solving gives x + y = 8.

- Mehr (mean) of numbers 12x, 12y is: (12(x + y))/2 = 48.

Option 3: 48