Question

Find the thirtieth term of the following sequence.
-6, -4, -2, 0, ...

52
64
66

Answer 1

There is not enough information for a unique answer.

You can make a broad, sweeping assumptions that the difference of +2 continues indefinitely, but the problem statement doesn't actually say that.

Answer 2

I guess I either have to count it out or guess...? That's literally all it gave me.

Answer 3

It is common to encounter poorly written problems of this type.

You do not QUITE have to "count it out". You can use your best algebra:

Find the thirtieth term of the following sequence.
-6, -4, -2, 0, ...

Term #1: -6
Term #2: -4 = -6 + 2
Term #3: -2 = -6 + 2(2)
Term #4: 0 = -6 + 3(2)

Getting the idea?

Term #15: -6 + 14(2) = ??

Term #23: -6 + 23(2) = ??

Term #30: Is what?