20 10 fill in the blanks in the third question of Jiangsu college entrance examination mathematics: there are three balls of the same size and 1 black ball in the box. If two balls are randomly drawn, the probability that the colors of the two balls are different is _ _ _ _ _ _ _.

Does this question refer to three balls or four balls? Do the three balls with the same size include the following 1 black balls?

If you count the other two balls, are they the same color? If not, are the three balls the same color?

None of this is explained in the title. It's sad that this kind of unclear topic appears on the college entrance examination paper! !

The answer to this question: no! ! ! ! ! !

What should candidates do? This is the level of Jiangsu college entrance examination. How to review college entrance examination questions?