Kenneth S. answered • 03/26/17

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Expert Help in Algebra/Trig/(Pre)calculus to Guarantee Success in 2018

I'll do the first part (b); substitution gives 50 = 15 + (80-15)e

^{-18.15k}because 18 min 9 sec = 18.15 min.35 = 65 e

^{-18.15k}0.543846 = e

^{-18.15k }and now we take natural logarithms to get-0.6190392 = -18.15k, so

k = 0.034106843. (I believe in using many decimal places, to minimize errors due to roundoff in forthcoming calculations; you may round the final answer when you do part (c)