Step 1 :Given the half-life of gold-194 is 1.6 days, we can set up the equation \( A(1.6) = A_{0} \cdot a^{1.6} = \frac{1}{2} A_{0} \)
Step 2 :Divide both sides by \( A_{0} \) to get \( a^{1.6} = \frac{1}{2} \)
Step 3 :Take the 1.6th root of both sides to solve for \( a \), resulting in \( a = \left(\frac{1}{2}\right)^{\frac{1}{1.6}} \)
Step 4 :Using a calculator, we find \( a = 0.5^{\frac{1}{1.6}} \approx 0.5^{0.625} \approx 0.755929 \)
Step 5 :\(\boxed{a \approx 0.755929}\)