Question

Brian opened a bank account that compounded continuously. The amount, y, in Brian's account can be modeled by this equation.
y=nekt
Where n is the initial amount deposited,
t is the time in years, and
k is the growth constant.
Brian deposited $500 initially and did not make any more deposits or withdrawals. After 8 years, Brian's account has a balance of $625.
What is the value of k?
O A k =
In(.8)
8
O c. k=
In(500)
5000
O B. k=
In(625)
4000
O D. k=
In(1.25)
8

Answer 1

9514 1404 393

Answer:

  D.  k = In(1.25)/8

Step-by-step explanation:

Solve the equation for k. Maybe you want to put the numbers in first.

  $y=n\cdot e^{kt}\\\\625=500e^{8k}\qquad\text{use the given values}\\\\1.25=e^{8k}\qquad\text{divide by 500}\\\\\ln{(1.25)}=8k\qquad\text{take the natural log}\\\\\boxed{k=\dfrac{\ln(1.25)}{8}}\qquad\text{divide by 8}$

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That's about 2.7893%