Let's write an equation describing the problem.
Any even whole number may be represented by writing

in which

is any non-negative integer.
It follows that for a even whole number

the next (consecutive) even whole number can be written as

.
We now need to solve the following equation:

If we solve for

we get:

We have to values, as the equation is quadratic. We take the positive one as the correct one. So

, and if we plug in this value to

and

we know that the
asnwer is 16 and 18.