I apologize unreservedly for saying your answer was wrong.
Both guest and I read it incorrectly as an increase of 5 every 5 minutes.
Thanks for subsequently taking the time to copy and paste your institution's answer so that we could see where our error lay.
Since it is a direct copy of your institution's answer, posting it could be a breach of copyright laws so I will remove it.
Next time I suggest you add the working in your own understood logic.
For others: The logic is exactly the same as guests except it is 5 a minute growth, not 5 every five minutes growth.
However.
I do not need to apologize for my first statement.
You have not expressed any gratitude for any help you have been given on any of your questions.
This answerer obviously spent a reasonable amount of time answering you.
Did you say thanks and then go on to explain why the answer was flawed? No of course you didn't.
You just gave a different answer, without thanks, recognition or explanation.
So my comment:
"Gee hmaser, your manners are just wonderful. (Strong sarcasm there)"
Still stands.
If you want to say that an answer is incorrect. Do so politely and back it up with your reasoning. (on the same post)