Question

280 grams of a radioactive substance decays to 100 grams after 500 years. To the nearest year, what is the half-life of the substance?

Answer 1

you can use
\[(\frac{100}{280})^{\frac{t}{500}}=\frac{1}{2}\] solve for \(t\) although you might have been taught differently

Answer 2

\[\Large A=A_0\left( \frac12 \right)^{t/H}\]
if H is the half life here...
\[\Large 100=280\left( \frac12 \right)^{500/H}\]

Answer 3

thanks