新G逻辑题求助。

okqishiUID: 3245371

废话不说，直接上题。
A low-pressure weather system is approaching Plainville; rainfall results from about 70 percent of such systems in the Plainville area. Moreover, the current season, spring, is the time of year in which thundershowers, which sometimes result from low-pressure systems,are most likely to occur in Plainville.
Knowing which one of the following, inaddition to the information above, would be most useful for determining the probability that Plainville will have a thundershower soon?
(A) the percentage of thundershowers in Plainville that occur in the spring
(B) the percentage of spring rainfalls in Plainville that are thundershowers
(C) the percentage of thundershowers in Plainville that result from low-pressuresystems
(D) whether low-pressure systems in other areas are associated with rainfall（B）
(E) whether Plainville has more or fewer thundershowers each spring than do nearby towns


我选的是C。答案是B。不知C为何错，也不知B对在哪...

米兰啸西风UID: 3136730

1# okqishi
这道题是将rainfall和thundershower混淆了。LZ可以画一下Venn图，rainfall和thundershower是有交集的，即：在70%下发生thundershower的可能性（题干中的sometimes）。也就是说rainfall和thundershower有多大的交集。（LZ要注意low-pressure只是个桥梁）

选项B就是解答了这个问题，就是这个交集越大，thundershower发生的可能性越大。
选项C不一定能增大thundershower发生的可能性。

okqishiUID: 3245371

2# 米兰啸西风
嗯，了解~