Explain how the number devil helps the author convince readers that mathematics is fun.
2 answers:
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Answer:
21. y = 75000·0.935^t
22. after 74.6 days
23. y = 27.8112·1.18832^t
24. 18.8% per month
25. 1748
Step-by-step explanation:
22. It is convenient to use the graphing calculator to solve this problem. The number of days is where the exponential curve has the value 500. It is about 74.55 days. (see the first attachment)
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23. y = 27.8112·1.18832^t (see the second attachment)
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24. The rate of change is the difference between the base of the exponential and 1, often expressed as a percentage. The time period is the units of t.
(1.18832 -1) × 100% ≈ 18.8% . . . . per month
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25. Evaluating the function for t=24 gives y ≈ 1748.30425259 ≈ 1748.
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<em>Comment on graphing calculator</em>
A graphing calculator can make very short work of problems like these. It is worthwhile to get to know how to use one well.
Divide the amount of teenagers that smoked by the total population:
Multiply this decimal by 100 to convert into a percentage:
To round to the nearest decimal place, look at the hundredths value:
8.53
3 > 5
8.53 -> 8.5
8.5% of teenagers reported that they smoked at least one cigarette.
Multiply this decimal by 100 to convert into a percentage:
To round to the nearest decimal place, look at the hundredths value:
8.53
3 > 5
8.53 -> 8.5
8.5% of teenagers reported that they smoked at least one cigarette.