SOLUTION: A 7-inch sunflower is planted in a garden and the height of the sunflower increases exponentially, increasing by 15% per day. a. Write a function f that determines the height o

Question 1124884: A 7-inch sunflower is planted in a garden and the height of the sunflower increases exponentially, increasing by 15% per day.
a. Write a function f that determines the height of the sunflower (in inches) in terms of the number of days t since it was planted.
b. How many days after it was planted will the sunflower be 28 inches tall?
c. How many days after it was planted will the sunflower be 143 inches tall?
Found 2 solutions by Boreal, josmiceli:
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
f(x)=7(1.15)^t
28=7(1.15)^t
1.15^t=4
t ln 1.15=ln 4
t=ln 4/ln 1.15=9,92 days
143=7(1.15)^t
1.15^t=20.43
round at end
ln both sides
t ln 1.15=ln 20.43
t=21.59 days
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!

b)

Take the log of both sides

days
c)

days
Get a 2nd opinion if needed

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