There is a clock on the screen. Use it.

You are probably spending too much time on problems you are getting wrong. Why spend 4 minutes on a problem you are going to get wrong regardless of the amount of time you spend on it.

In business you allocate your time to things according to importance and other factors. Here you need to allocate your time based on chance of getting the question right and amount of time it will take you to answer. Cut your loses when you know you don't know how to do a problem skip it. I bet you stare at the screen and then try to figure it out a few times and guess. This time could be used on a new question you know how to answer.

Hi i am also facing the same problem and waiting for reply.

Here's my 2 cents on this KEY topic (on timing).

On average you should be spending 2 minutes per question. When I tackled my first practice test, I quickly found that I was answering some questions faster and others longer ... so instead of trying to get EVERY question answered within 2 minutes ... I try now to use the following approach:

I have a number of CHECK-POINTs ... these are certain times within the exam, where I take a quick look at the time remaining and the question I should be on.

See below.
75 mins left - Start on Q1
65 mins left - I should be on Q6
55 mins left - I should be on Q11
45 mins left - I should be on Q16
35 mins left - I should be on Q21
25 mins left - I should be on Q26
15 mins left - I should be on Q31
5 mins left - I should be on Q36
Leaving 5 minutes for the final 2 questions.

I find this helpful ... instead of trying to manage EVERY question under the 2 minute deadline ... I have broken the section down into managable chunks and defined these checkpoints.
Some people may choose to break it down even further, for example:
75 mins left - start Q1
50 mins left - should be on Q14
25 mins left - should be on Q28

hope this helps. I think Timing is half the challenge for the GMAT ... all I can say is that practice practice practice make perfect.

Also, depending on where you are (in terms of timing) in the test ... if you are on track, behind schedule, ahead of schedule ... you can vary the point in time at which you make an educated guess before moving onto the next question, for a question which you are struggling with.
For example.
I am on Q11 ... the clock tells me I have 58 minutes left ... (according to my check-point ... I should have 55 minutes left if I was on track ... this means I am ahead of schedule ... and have some extra time to spread out amongst the remaining questions ... this means that I can take slightly longer in answering the more difficult questions (but be careful to keep your eye on the schedule). So if Q11 is tough, and presenting me with difficulties, after spending 1 minute or 1.5 minutes you should normally be looking to make and educated guess and move ... however, in this scenario, I have a bit more time to play with, as I am ahead of schedule.

Hope this makes sense.
II