If you're only supposed to do 10 reps per set, and only 3 sets for per muscle group for muscle building, it seems like weight lifting workout only lasts about 30 minutes. is that too quick?

Fine: Make sure you include 10 minutes of progressively higher intensity cardio and stretching as a warm up and then 30 minutes of weights and 5 minutes of cool down and stretching and you will have an excellent work out.

Not correct: There is no rule to limit sets or reps. I do several separate exercises in sequence of15 reps each and repeat the entire cycle 4 times.