Sum of two numbers = 16 difference of the numbers = 6 find the numbers. what if their product?

Numbers x and y
sum of the two = 16: x + y = 16
difference of the two = x - y = 6
solve one of the equations for one variable:
I'm going to solve x - y = 6, for x
(x - y) + y = 6 + y, x = y + 6
Now plug that into the other equation:
x + y = 16, (y+6) + y = 16
(y+y) + 6 = 16
2y + 6 - 6 = 16 - 6
2y = 10
2y/2 = 10/2
y = 5
Now plug that solved y-value into either original equation: x - y = 6, x - 5 = 6
(x-5) + 5 = 6 + 5
x = 11
So now we have their values: x=11, y=5
But always double-check what the question asked... What is their product??
So x*y = 11*5 = 55

The correct answer is c