According to the diagram shown on the sides of a single dice, the letters are G, H, I, J, K and L. What is the letter on the opposite surface of the letter K?

The logic followed here is :-

From the given two different cubes the adjacent sides are as shown below :

As H is common on both the dice, it is clear that G, I, L and K are adjacent to it and remaining number i.e., J will be opposite to it.

Opposite pairs:

G → L

I → K

H → J

So, the opposite side of "K" will be side "I".

Hence, the correct answer is "I".