Data Sufficiency

What are the speeds of two trains 80 m and 85 m long respectively?
(A) They take 37.5 seconds to pass each other when they are both running in the same direction
(B) They take 7.5 seconds to pass each other running in opposite directions


1. statement (A) alone is sufficient but statement (B) alone is not
2. statement (B) alone is sufficient but statement (A) alone is not
3. both (A) and (B) together are sufficient but none of them alone is sufficient
4. both statements are sufficient independently
5. both (A) and (B) together are not sufficient


Please provide your answer with explanations...thanks in advance

IMO D

IMO D

I think the answer is C
Because the statements provide us with the relative velocities of the 2 trains..
1. gives us u-v
2.gives us u+v
where u and v are the velocities of the two trains.
so using both the statements we can find out the individual values of u and v.

Can someone tell me whther i am right?!

ps: i dont know the terminology being used in this forum.. wat do OA and IMO stand for?!!

IMO C

agree with above explanation.

The answer to the above is definitely C. This is based on the concept of relative velocity. If you tried to use Total distance/Total time you will get two different set of values which are infact relative velocities U-v and U+V.

i hope we don't have to know this on the gmat.... i thought it was D, too..