In the first one "tries" would be the right word to use, but there are more natural ways to say it, for example:
"I had to take/took the test 4 times before I finally passed". Either "had to take" or "took" would be fine.
In the second it's not at all clear what you are trying to say.
In the third, "trials" would also be correct, but once again it's not very natural, better would be: "Please give me another try".
The meaning of the third is not at all clear.
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