depends upon the difficulty level of the question..

well i would say on an avg one should not take more than 1.3 min to solve a SC prob

Hi, I have read some BTG articles of 750+ GMAT achievers and they propose the following time tactic:
1. With the first third of the test, you do it thouroughly and roughly take you 1m45 - 2m per question. Because this part's used to determine your supposed score.
2. The second third, you should do it faster as it coutains some experiment questions (4-5). So, reduce your time spend to 1m to 1m30.
3. The last part of the test, you should treat it carefully and spend around 1m45 - 2m per question. Especially, some hard questions, you could spare them around 2m30 but be short in others . Because this part will agian be used to determine your final score.
I'm not sure the above tactic is correct or not. But I hope it could partly help.
How do you think , peer ?