Question

A(t)= 135(.917)^t represents the amount of substance, A(t) given the number of days t How much of the substance will be left after 18 days Find A(18)
28
25
29
39

Answers

GPT-4o mini
To find the amount of the substance remaining after 18 days using the given formula \( A(t) = 135(.917)^t \), we will substitute \( t = 18 \) into the equation.

\[
A(18) = 135 \times (0.917)^{18}
\]

Now, we calculate \( (0.917)^{18} \):

\[
(0.917)^{18} \approx 0.283
\]

Next, we multiply this value by 135:

\[
A(18) \approx 135 \times 0.283 \approx 38.205
\]

Rounding this to the nearest whole number, we get:

\[
A(18) \approx 38
\]

From the provided options (28, 25, 29, 39), the closest answer is **39**.

So, the amount of the substance left after 18 days would be approximately **39**.