2012-06-01 09:00:15

If x&y = x²y and x@y = 2x + y, what is (2&3)@5?

(A) 22
(B) 29
(C) 44
(D) 52
(E) 59

The correct answer is B

Explanation: Symbol questions work the same way as functions. Whatever is in place of x on the left side of the equation takes the place of x in the actual equation (and the same goes for y). Order of operations applies here too, as the function that is in parentheses must be solved first. The solution to that expression will become the x-input in the second expression. Thus, plug 2 in for x and 3 in for y in the x&y function:

2&3 = (2²)(3), or 4(3), which is 12.

Now, use 12 in place of x in the x@y equation: 12@5 = 2(12) + (5), which is 29, making choice B the correct answer.