saurabhm99 wrote: I am considering a hypothetical situation where the distance b/w the 2 is very far , but as the speed of policeman is 2 times the thief, the policeman will ultimately catch hold of the thief(even after a very-very long time), so A should be sufficient.

I think you misread the target question. It reads, "When will the policeman be able to catch the thief?" In other words, how much time will it take for the policeman to catch the thief?

I think you're reading it as, "Will the policeman be able to catch the thief?"


Aside: the wording of the sentence is somewhat ambiguous. Asking "when," could be read as "At what time will the policeman catch the thief?" (midnight? 4:20pm?)

Cheers,
Brent

saurabhm99 wrote:This is a data sufficiency question

A policeman spots a thief and runs after him. When will the policeman be
able to catch the thief?
(1) The speed of the policeman is twice as fast as that of the thief.
(2) The distance between the policeman and the thief is 400 meters

Target question: How much time will it take the policeman to catch the thief?

Statement 1: The speed of the policeman is twice as fast as that of the thief.
We have no idea how far they are apart initially. They could be 1 meter apart or they could be 1 million meters apart.
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: The distance between the policeman and the thief is 400 meters
We have no idea of their respective speeds.
It may even be the case that the thief is faster, in which case the policeman will never catch the thief.
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined:
We still don't know the speeds of the two people. Consider these two conflicting cases:
Case a: thief's speed = 1 meter per second, and policeman's speed = 2 meters per second. So, with each second, the policeman will get 1 meter closer. With a 400-meter gap to close, it will take 400 seconds to catch up
Case b: thief's speed = 10 meters per second, and policeman's speed = 20 meters per second. So, with each second, the policeman will get 10 meter closers. With a 400-meter gap to close, it will take 40 seconds to catch up

Since we still cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent