The school bus always stops at the railroad tracks. When the

Question

The school bus always stops at the railroad tracks. When the warning light is not flashing, it then proceeds directly across if the tracks are clear. However, when the warning light is not flashing and the tracks are not clear, the school bus waits until they are clear and then proceeds immediately across them.

If ths statements above are true and it is true that the school bus stops at the tracks and then does not proceed to cross them, which of the following must also be true?

(A) The warning light is flashing and the tracks are clear.
(B) The warning light is flashing and the tracks are not clear.
(C) The warning light is not flashing and the tracks are not clear.
(D) The warning light is flashing, or the tracks are not clear, or both.
(E) The warning light is not flashing, or the tracks are not clear, or both.

mohish · Answer

go C go...

On second thoughts...go E go...

Antmavel · Answer

B for me

it is said that the bus doesn't cross the road so it means that it has to be with a flashing light. 

We know that :
- When the warning light is not flashing, it then proceeds directly across if the tracks are clear. 
- when the warning light is not flashing and the tracks are not clear, the school bus waits until they are clear and then proceeds immediately across them

However now the bus has stopped and then does not proceed to cross. So it can only be with a flashing light. D is out because the only condition that the tracks are not clear is not sufficient (it is said that if tracks no clear but no flashing, the bus proceed).

It can only be A or B
B is more logical, if the tracks no clear the bus wont go...in A if it was just the light it would have stopped but then it would have proceeded...

nakib77 · Answer

i will go with B.

an_narang · Answer

I'll go with D

gamjatang · Answer

Thanks for the discussion.

The OA is (D).

ywilfred · Answer

The bus stops because the premise says the bus ALWAYS stops at the railroad tracks. This is irrespective of whether the lights are flashing or not.
The decision to wait is then made once the bus comes to a stop.

I feel A,B and C are out because it lumps the decision process into a "AND" of two items: State of the lights and whether the tracks are clear
E is out as it says the light is not flashing is sufficient to prevent the train from moving

D is the best choice. If the lights are flashing, then the train can't move. If the tracks are clear, then train can move. If both happens, the train can't move either. 

D for me

Antmavel · Answer

I think I overlooked at the stem :cry:

in D it is said that "The warning light is flashing, or the tracks are not clear, or both." in the stem we have "When the warning light is not flashing and the tracks are not clear, the school bus waits until they are clear and then proceeds immediately across them" and the question is "if it is true that the school bus stops at the tracks and then does not proceed to cross them, which of the following must also be true" In the question, I understood that the bus is not crossing the tracks at all. It is still stopped. This ws my understanding. However if you say that D is OA it means that the bus only stopped for a while and then crossed the road. Moreover if D is right it means that for example if the tracks are not clear (whaetever the flashing light) it should be sufficient but we know from the stem if it is so without a flashing ligth the bus will stop and then go on. I think I misunderstood the question. I thought the question said that the bus is still stopped and doesn't proceed at all...sorry :wink:

ywilfred · Answer

The bus is stopping because the arguement tells us the bus will always stops whenever there is a railway track. This is regardless of whether the light is flashing or not. Once the bus comes to a stop, then the decision making process starts: Whether light is flasing -> whetehr track is clear etc. It's like the if-else loop in computer programming.

I think the question meant that it does not cross the track immediately, so your understanding that it stopped, made some deicision, then crossed the track.

D is the best chocie as I explained previously.

GMATT73 · Answer

Another vote for D. Clearly the bus won`t cross the tracks for one of two reasons: either the tracks are not clear or the lights are flashing.

The school bus always stops at the railroad tracks. When the

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