Question

22. Use your model to determine when the volume of oil will get down to 500 gallons.

Answer 1

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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Comment on graphing calculator

A graphing calculator can make very short work of problems like these. It is worthwhile to get to know how to use one well.