I have no clue. One of my warm-ups often include up to 50. Note I said, "warm-ups."
The pic here was taken during Murph, a memorial workout that consists of a 1 mile run, 100 pull-ups, 200 push-ups, 300 squats and then another mile run. That's me over there, catching my breath.
I like push-ups and I do them until I can't do any more. The great thing about push-ups is that you can take them anywhere. Can't take a bench-press with you wherever you go, but you can push your body up off the floor. I'm not a Navy person, but if I was on a ship getting tossed about in 40 foot swells, you would not find me on a bench press.
Push-ups is just one training exercise that taught me that I can accomplish what I set my to accomplish. I had no plan but to finish. If I have 50 or 100 or 200 to do, I push myself to finish. The same is true with many things in my life. Finish.
Finish sweaty, finish hurting, but finish. Dig deep, but finish.