b. The expression $225 \cdot\left(\frac{1}{2}\right)^{\frac{1}{2}}$ represents the amount of medicine in the body some time after it is administered. What is that time?
\(\boxed{0.5}\) hours (30 minutes) after it is administered.
Step 1 :Let \(A(t) = 225 \cdot\left(\frac{1}{2}\right)^t\) represent the amount of medicine in the body at time \(t\) hours after it is administered.
Step 2 :We want to find the time \(t\) when \(A(t) = 225 \cdot\left(\frac{1}{2}\right)^{\frac{1}{2}}\).
Step 3 :Set up the equation: \(225 \cdot\left(\frac{1}{2}\right)^t = 225 \cdot\left(\frac{1}{2}\right)^{\frac{1}{2}}\)
Step 4 :Solve for \(t\): \(t = \frac{1}{2}\)
Step 5 :\(\boxed{0.5}\) hours (30 minutes) after it is administered.