Question: how to do 20 pull ups in 2 weeks?
Answer: Many raised their pull-ups to 10-20 in two weeks. Take your current pullup max effort score and multiply by 5. That is your daily number of pullups. So if you can do 10 pullups in one max rep set and fail at 11, then you need to do 50 pullups a day in a total repetition count of your workouts.