This could quite possibly be…
On a rowing machine row 300m as fast as possible.
What ever this time is, is the time you have to do as many push-ups as possible. So if it take 55 seconds to row 300m, you have 55 seconds to do as many push-ups as possible. Repeat this cycle until you have done 300 push ups.
There’s a catch though (and here’s the hard bit). For every second over 60 seconds it takes to row 300m, you have to do a burpee before you start your press-ups. So if it takes 65 seconds to row 300m, that’s 5 burpees then as many push-ups as possible in 65 seconds.
I don’t feel ready to tackle this one just yet, but might try it next week… or the week after… maybe.