Treat \(i\) like a variable and combine like terms.
How are you still awake? Imma go to bed soon. Sorry.
Please tell me you're not trolling
And anyway, the answer wouldn't be 0. It would be 000. Know the difference.
The so on is meant to say that this continues until you get down to the last room.
You're reposting a problem. Again. Did you not get it last time? I'm pretty sure you said you did.
Read the problem: it says there are a very large number.
This sounds like the meme where the guy asks if n is a lot.
First room: \(\binom{20}{2}\)
Second room: \(\binom{18}{2}\)
And so on. Use multiplication I think. Someone check my work because knowing these types of problems there's usually a catch or my method is completely wrong.
Aww... I thought I was getting somewhere...
Or don't be an idiot like me and use modulo to find it easily. Your call.
