I agree with 18.

Is it this simple? The answer is Please. Answer = Please.
Very tricky.

That is assuming 3 is multiplied by 4 and the sequence is not supposed to that 3 is multiplied by 6.

When logic and proportion
Have fallen sloppy dead,
And the White Knight is talking backwards
And the Red Queen's "off with her head!"

Just call Alice!!


Shades of Gracie.... Slick, that is.





.

I'd flunk it. None of the equations are right. 3= 3

9 does not = 90
8 doesn't = 72
and so forth.

Only when the "Math test" offered is preceded by the word "Assume", and ended by asking "then 3 equals what?", would it be a valid question.

You got it!!

Feed your Hare

Hunting season is open!

I go with 18. The difference between them on the right decreases by 2 until the last gap, while the difference on the left side stays at 1. When you get to the 3, the difference on the left is doubled, so if you double the math on the right you get 18. This solution gives you consistent math in both columns.

looks like 12