Not all at once
Your hours will be 0600 to 2230, that is you have a 16 hour day every minute of which is scheduled and accounted for. You may get excited when you hear of an hour or so of "personal maintenance" time in each evening, however that will be taken up with things like ironing, repairing uniforms, polishing boots and brass, etc. There's every chance you'll have a letter from your girlfriend or mum in your pocket that's still unread after a week, or if read not replied to - by the time you have time you just want to lie down and sleep, and anyway what will you say? There's both everything and nothing to tell them.
During a 16 hour day you can easily do hundreds of pushups. If you can do 20, well 20 in each hour over the 16 hours, there you go that's 320. Usually there are few after dinner, though, they happen mostly during the day. It's generally 20 a time for punishment in the first week, then 30 in the next, then 40 after that, and then 50 for a couple of weeks. Once everyone can knock out 50 without trouble, they drop it down to about 30 for maintenance.
You don't get situps for punishment as it messes up the uniform too much. So the PTIs will make up for it in the PT sessions, along with jumping jacks and burpees and all the rest.
Again, I can prepare you for this. I'd suggest a weekly visit to the city for a casual jaunt around the park.