Yeah I agree, but may be relationship holds for x and y and not just for x, so may be it will not work for x@x, which will just be x

Given that \(x @ y = \frac{x - y}{3}\) and we need to find the value of \(3 @ (11 @ 2) =\)

Lets start by finding the value of 11 @ 2

To find 11 @ 2 we need to compare what is before and after @ in 11 @ 2 and x @ y

=> We get to substitute x with 11 and y with 2 in x @ y to get the value of 11 @ 2

=> \(11 @ 2 = \frac{11 - 2}{3}\) = \(\frac{9}{3}\) = 3

=> \(3 @ (11 @ 2) =\) 3 @ 3

Using what we learned above, \(3 @ 3 = \frac{3 - 3}{3}\) = \(\frac{0}{3}\) = 0

So, Answer will be C
Hope it helps!

Watch the following video to learn the Basics of Functions and Custom Characters