A Penteria is a special (fictional) kind of bacteria such that, regardless of the original population in a collection, the population increases by 5 every minute. Additionally, at the end of every hour, all but the initial ones die. If 137 Penteria are alive after  506 minutes, how many were there at the beginning?

 Feb 14, 2021

506 minutes is 8 hrs 26 minutes

    so the 'initial ones' have had 26 minutes to reproduce

      26 minutes is  five  5 minute periods       so the increase is 5 x 5 = 25


137 - 25 = 'initial ones' = 112

 Feb 14, 2021

...as an edit ....    PERHAPS you could say since there is ONE minute more than five 5 minute periods, that ONE more bacterium was produced

           (but the question does NOT say the bacteria reproduce 1 per minute....it says  5   every 5 minutes)


SO if you go with the one extra bacterium     137 - 26 = 111 originals .....

Guest Feb 14, 2021

there is 7 bacteria at the start. 

 Feb 14, 2021

Gee hmaser, your manners are just wonderful.  (Strong sarcasm there)

Your answer is wrong.  If you want to justify it then go ahead and do so.

Melody  Feb 14, 2021

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.



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)

 Feb 15, 2021

ok. thank you for the help melody. I am sorry for posting that picture and for accusing you. I was in the wrong. Thanks for everything you do. I hope you can forgive me. I will not do it again. 

hmaser  Feb 17, 2021

Don't worry about it.  We were both in the wrong.  

Just remember to respond positively to people when they try to help you.

If they are wrong take the time to find their error or at least post an explanation of why they are wrong. (the correct answer)


Even if it is just as simple as :

"Thanks, but I think your answer might be wrong because when I put your answer in the box the response said 'wrong' "


Although, a proper explanation, if you have one, would be a lot better.

Melody  Feb 17, 2021

Ok. Thank you for telling me Melody. 

 Feb 17, 2021

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