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
