I am not totally understanding why (E) is wrong . Is it not saying the exact same thing as (B)? If Cindy flies with Dave on plane 3 why does Bob need to fly plane 2? My understanding is that Dave flies in plane 2 he needs either Bob or Cindy. So essentially it looks to me like (B) and (E) are saying the same thing. I answered all the other questions quickly with no problems but this one is not making sense hahah.
Thanks for the question! Answer choices (B) and (E) are not identical, and the difference between them is one worth studying
The key to the problem is knowing that Dave must fly with Bob or Cindy. This condition has to be met, and so it controls what occurs. But, in this particular problem, we also know from the question stem that Dave flies in plane 2
. Now, compare that to (B) and (E), where I've added italics for emphasis:
- (B) If Cindy flies in plane 3, Bob flies in plane 2.
(E) If Cindy is in plane 2, Bob flies in plane 3.
So, in answer choice (B), when Cindy flies in plane 3, who is left to fly with Dave in plane 2? Only Bob remains available because Cindy is in 3 and Anna is in 4. Thus, the second half of (B) must occur: "Bob flies in plane 2." Answer choice (B) must be the case then.
Now look at answer choice (E). Once Cindy is in plane 2
, then Dave is covered since he has a pilot. What does that do to Bob? Nothing at all, and he's now free to go wherever he wants. He definitely doesn't have to fly in plane 2 because Dave is already covered by Cindy being in plane 2.
Knowing Dave is in 2 and needs Bob or Cindy is the key, and then look at how each answer starts—where Cindy goes (or doesn't go) makes all the difference!
Please let me know if this helps, thanks!