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Learning Theory The average typing speed N (in words per minute) after t weeks of lessons is modeled by

N = 95/1 + 8.5e^-0.12t
find the rates at which the typing speed is changing when (a) t = 5 weeks, (b) t = 10 weeks, and (c) t = 30 weeks.

1 Answer

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Answer:

(a) 17 words per minute

(b) 27 words per minute

(c) 77 words per minute

Explanation:

N = 95/1+8.5e^-0.12t

(a) t = 5 weeks

N = 95/1+8.5e^(-0.12×5) = 95/1+8.5e^-0.6 = 95/1+8.5(0.55) = 95/1+4.675 = 95/5.675 = 17 words per minute

(b) t = 10 weeks

N = 95/1+8.5e^(-0.12×10) = 95/1+8.5e^-1.2 = 95/1+8.5(0.3) = 95/1+2.55 = 95/3.55 = 27 words per minute

(c) t = 30 weeks

N = 95/1+8.5e^(-0.12×30) = 95/1+8.5e^-3.6 = 95/1+8.5(0.027) = 95/1+0.2295 = 95/1.2295 = 77 words per minute

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