Explanation:

Let's find the pattern in the operation:

Given:

- 11 # 2 @ 6 = 78

- 15 # 4 @ 8 = 152

Let's try to relate input numbers to the answer:

- (First x Second) + (Second x Third)

- (11x2) + (2x6) = 22 + 12 = 34 (But not 78)

- (First x Third) + (Second x Third) = (11x6) + (2x6) = 66 + 12 = 78

Now check second:

- (15x8) + (4x8) = 120 + 32 = 152

So, the rule is:

- (First x Third) + (Second x Third)

Now for:

17 # 6 @ 7 = (17x7) + (6x7)

= 119 + 42

= 161

Let's check the options:

- Option:1, 161

- Option:2, 143

- Option:3, 221

- Option:4, 157

Correct Answer: Option 1, 161

- The operation is (First x Third) + (Second x Third)

- Applying it gives 161 for the last equation

- Option 1 is correct