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1. |
Radioactivity The half-life of uranium-232 is 72 years. Find the approximate value of k in the formula y = nekt for uranium-232. Assume t is in years. |
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A. |
-0.0048 |
B. |
-0.0096 |
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C. |
-0.0024 |
D. |
0.0012 |
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Hint |
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2. |
Population The population of Redville grew from 5432 in 1990 to 7116 in 2000. Assuming the population is growing exponentially, predict the population of Redville in 2005. |
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A. |
about 8360 |
B. |
about 8290 |
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C. |
about 8140 |
D. |
about 7960 |
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Hint |
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3. |
A Mickey Mantle rookie card appreciates in value 2% every year. How much was it worth in 1990 if it is worth $35,000 in 2000? |
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A. |
$42,665 |
B. |
$28, 712 |
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C. |
$5653 |
D. |
$216,711 |
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Hint |
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4. |
Two cities have insect problems. The insects in City A increase exponentially according to the equation y = 120,000e0.04t. The insects in City B increase exponentially according to the equation y = 90,000e0.08t. In 15 years, which city will have more insects, and by approximately how much? |
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A. |
City B, by about 30,000 |
B. |
City A, by about 80,000 |
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C. |
City A, by about 30,000 |
D. |
City B, by about 80,000 |
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Hint |
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5. |
Suppose a new car loses value at 10% per year for the first 5 years. When should the owner sell it if they want to receive 75% of what they paid for it? |
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A. |
after 2.5 years |
B. |
after 3 years |
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C. |
after 2 years |
D. |
after 2.73 years |
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Hint |
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