How many exercises should I have in a complete workout?

Depends entirely on what you're trying to do.

your average weight lifting workout is best completed in around 45 min. I've worked out at times 3 hours a day 6 days a week. A cardio can be as quick as 20 min. For losing a few pounds and building a little muscle can be done in 30 to 45 min. the amount of exercises isn't really important as long as you only take 15-30 seconds between sets and around a 1- 1:30 minutes between exercises. on leg day i do 3- 4 exercises with a 10 minutes of cardio for warm up or calisthenics and abs included each day.

How about you exercise that brain of yours and educate yourself before you answer anymore questions about fish.