[Other] Household expenses common bank account, Plus LLM

Question: We have 3 bank accounts. Account 1 is on person A. Account 2 is on person B. Account 3 is used by both. Person A and B both add the same amount on account 3. For example if A adds 100 euros B will also add 100. Now if A makes a purchase for 70 euros that is for both, but pays from account 1, how much money should he take from account 3 to be correct? Also if he doesn't take from account 3 how much should he take from account 2?

Chatgpt 4o:

https://chatgpt.com/share/686912f0-c6bc-8010-9e18-bf18f0420a7d

Chatgpt o3:

https://chatgpt.com/share/68691327-6a8c-8010-804b-4e6fd79ad2cd

Gemini flash:

https://g.co/gemini/share/c1e6b40a48aa

Gemini Pro: https://g.co/gemini/share/1ff4315920ee

Personally I had thought that 52.5 would be the correct but I guess I am wrong. What would the correct answer be here? Sorry for formatting I am on mobile