Answer:
B. A(r(t)) = 25πt²
Step-by-step explanation:
Find the completed question below
The radius of a circular pond is increasing at a constant rate, which can be modeled by the function r(t) = 5t where t is time in months. The area of the pond is modeled by the function A(r) = πr². The area of the pond with respect to time can be modeled by the composition . Which function represents the area with respect to time? A. B. C. D.
Given
A(t) = πr²
r(t) = 5t
We are to evaluate the composite expression A(r(t))
A(r(t)) = A(5t)
To get A(5t), we will replace r in A(t) with 5t and simplify as shown
A(5t) = π(5t)²
A(5t) = π(25t²)
A(5t) = 25πt²
A(r(t)) = 25πt²
Hence the composite expression A(r(t)) is 25πt²
Option B is correct.
We have been given that Bobby's investment of $225,000 loses value at a rate of 3% per year. We are asked to find the value of the investment after 10 years.
We will us exponential decay function to solve our given problem.
We know that an exponential function is in form
, where,
y = Final amount,
a = Initial amount,
r = Decay rate in decimal form,
x = Time.
Let us convert 3% into decimal.

Upon substituting
,
and
, we will get:




Upon rounding to nearest dollar, we will get;

Therefore, the value of the investment after 10 years would be
.