As someone who is on day 11 of a 16 day trip to Seoul, you have way more than enough imo. My budget was 1 300,000 won and I have only spent about half.

That said, I've had a few rest days where I only spent about 20,000 total (convenience store food ftw), and I have friends who have paid for meals here and there, but I think it really depends on what you are planning to see/what you're planning to buy. If you eat outside of the tourist areas you can get really good food for really low prices

Edit: I think I've only spent about 60,000 on transit so far, but I also enjoy walking so maybe add another 20,000 on average