According to the Answers page the correct answer is A, meaning that statement 1 is sufficient.

I believe it is not, since we don't know how many different colors are in the jar.
For example if there are 3: White=2*X, ColorA=X, ColorB=X. therefore the probability of picking a white ball is 50%.
if there are 2 balls: white=2*x and ColorA=x, the probability of picking a white ball is 75%.

Anyone who has an opinion about that?

I think you might be misinterpreting the wording here.
The meaning is that there are 2x white balls and the sum of the other balls, including balls of ANY other color, is x.
Thus, the answer is A.

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