so you can't stay.
What's the diff? You'll start way early tomorrow, and by 10am, you'll both be in the same spot.
If he starts at 3:20, when will he finish them? Let's say 4. And if you started them then, how far would you get before 5? And if you came in at 7:30, and they're ready for you, at 8:30am, you'll be as far along as you would be at 5pm.
This way, he can make up the solutions, double-check his work, methodically label them, and they'll be ready for you in the morning.
Good for you, standing strong on your schedule.