# math problem

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• Mar 3rd 2009, 11:42 PM
kenkarylle5
math problem
imagine five mold spores on a piece of cheese in your refrigerator. suppose that the spores triple in number every hour

A) make a table showing the mold spore count for the five hours?

B) write an algebraic model for this situation. clearly define your variable. explain how the model relates to the table

C)you can visually detect the mold when there are one million spores. how long does it take you to see the mold? document your reasoning in a clear and organized manner?

hope you could help me
• Mar 4th 2009, 12:03 AM
JeWiSh
A) Well if you start with 5, and they triple with every hour then just write out a table of how many there are after 0, 1, 2, 3, 4 and 5 hours. E.g 0 hours - 5, 1 hour - 15.

B) So it's asking you to create a formula to describe the growth of the mould. I'll give you a hint, it involves using n (the time in hours) as a power, since the growth is exponential.

C) If you can create this formula it's easy, just plug in that it equals 1,000,000 and you should be able to find n.

See how you get on.
• Mar 4th 2009, 12:33 AM
kenkarylle5
so it will be like y=5(3)^n or y=3(5)^3...

im stuck ryt now..

dunno if i did it ryt
• Mar 4th 2009, 12:43 AM
JeWiSh
Quote:

Originally Posted by kenkarylle5
so it will be like y=5(3)^n or y=3(5)^3...

im stuck ryt now..

dunno if i did it ryt

Yeah that's right, $y=5(3^n)$. Just think about it, after 1 hour there's (3*3) * 5, after two hours (3*3*3) * 5...
• Mar 4th 2009, 12:49 AM
kenkarylle5
ahahahaha thank you so muchhh

appreciate it...
• Mar 4th 2009, 12:54 AM
JeWiSh
Quote:

Originally Posted by kenkarylle5
ahahahaha thank you so muchhh

appreciate it...

Anytime, you can press 'Thanks' if you like ;)