请教

tomato

新东方数学册中 Data Sufficiency中Section19里的两题：
9. The figure above shows the present position on a radar screen of a sweeping beam that is rotating at a constant rate in a clockwise direction. In which of the four quadrants will the beam lie 30 seconds from now?
(1) In each 30 second period, the beam sweeps through 3.69
(2) r=40

16. What is the probability that events A and B both occur?
(1) The probability that event A occurs is 0.8
(2) The probability that event B occurs is 0.6
答案是E, 没想通

多谢指教！

tongxun

16、要考虑A、B两事件是否为孤立事件。是与否就代表了两个答案，所以我认为是：E

明天zhouxh将会详细回答

zhouxh

恩，16题选E.这种题应该就是考独立性的.因为
p(a∪b)=p(a)+p(b)-p(a∩b).不知道ab是否独立.p(a∩b)的值无法确定！

9题能把figure贴出来吗？我没有新东方的教材