08G-28 An insect pest population doubles every 18 days. If an insecticide kills 90% of the insects, how often should it be applied to keep in insect population in check?
Answer: 59.8days
07E-36 Fred invests $10,000 for 2 years. He would make $200 more if the interest was compounded monthly instead of annually. What is the annual interest rate?
Answer: 13.6%
07D-38 Rich deposits six, consecutive monthly payments of $100 each at 3% annual interest compounded monthly. How long after the last payment will he have a total of $1000?
Answer: 16.8yr
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Exponential Questions
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Exponential Questions
by calcguy1350 » Tue Apr 10, 2012 9:12 pm
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Re: Exponential Questions
by 007math » Wed Apr 11, 2012 12:31 am
3rd Place State Mathematics 5A 2012
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Re: Exponential Questions
by redhawk2015 » Wed Apr 11, 2012 7:31 am
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Liberty HS, Frisco - 4A (District 9, Region II)
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Re: Exponential Questions
by 88bobcat » Wed Apr 11, 2012 10:19 am
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Re: Exponential Questions
by 88bobcat » Wed Apr 11, 2012 10:44 am
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Re: Exponential Questions
by Shawn » Wed Apr 11, 2012 6:26 pm
Just another solution on the "in check" type problems:
28)
A)How many times can the population grow before it is "out of check?" 10, because if we have 10 bugs we can get it back down to 1 or "in check."
B) How many times is this "doubling?"
[unparseable or potentially dangerous latex formula]
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So how long to double that many times?
[unparseable or potentially dangerous latex formula]
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88bobcat's solution works and is effectively the same thing, just figured I would give you an intuitive way of figuring it out.
28)
A)How many times can the population grow before it is "out of check?" 10, because if we have 10 bugs we can get it back down to 1 or "in check."
B) How many times is this "doubling?"
[unparseable or potentially dangerous latex formula]
[unparseable or potentially dangerous latex formula]
So how long to double that many times?
[unparseable or potentially dangerous latex formula]
[unparseable or potentially dangerous latex formula]
88bobcat's solution works and is effectively the same thing, just figured I would give you an intuitive way of figuring it out.
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