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1. The probability that event A will occur is 0.5. The probability that event B will occur is 0.4. The probability that event A or B will occur is 0.8.

Column A：Probability that A and B both occur

Column B：0.1

A. The quantity in Column A is greater

B. The quantity in Column B is greater

C. The two quantities are equal

D. The relationship cannot be determined from the information given

2. Yesterday, at a certain school, the ratio of boys to girls was 1 to 3. Today, an equal number of boys and girls joined the school. The number that joined was greater than zero and no students left.

Column A: Ratio of boys to girls now

Column B: 1/3

A. The quantity in Column A is greater

B. The quantity in Column B is greater

C. The two quantities are equal

D. The relationship cannot be determined from the information given

参考答案：1C 2A