Find the half-life (in hours) of a radioactive substance that is reduced by 15 15 percent in 75 75 hours.

Answer 1

0.85 = e^75k

ln 0.85 = 75k

-0.1625 = 75k

-0.0021669 = k

0.5 = e^kt

Can you substitute k, solve for t, and answer?

Answer 2