you should try to keep it under 5 minutes.
since there will be easier ones and harder ones, its ok to take up to 10 minutes on a test as long a you try to get the easy ones done first. if you can skip questions then go back to them later, do the hardest ones first thengo back and do the easier ones afterwards.
Try to take your time when you need to. if you get stuck, think about what it says. Try to think of it another way. You also want to get as much done as you can, this is because if you miss 5-10 questions, the grade could be seriously decreased, as you might have gotten a few other questions wrong.
Make sure to do a "QC" as I call it; or a "Quick Check." If it looks good and it's reasonable then you are fine to move on. it it doesnt look right, retrace your steps. Then rewrite it if you got something else on your next try for the QC.
I hope you do good!
May luck be with you!