i have to develop a test generator that picks 10 out 0f 20 questions from a textfile that i have already finished can some one please help

Telling us what language it's in may be a good start.

Never mind, I see that it is in 'Java'. I don't know Java, can't help you there... but you may want to research if Java has anything like Python's .shuffle(), as it might do what you want.