Free Decay Calculator - Determines decay based on an initial mass and decay percentage and time.

Free Exponential Growth Calculator - This solves for any 1 of the 4 items in the exponential growth equation or exponential decay equation, Initial Value (P), Ending Value (A), Rate (r), and Time (t).

Free Half-Life of a Substance Calculator - Given a half-life (h) of a substance at time t, this determines the new substance size at time t_n, otherwise known as decay.

Plutonium 241 has a decay rate of 4.8 % per year. How many years will it take a 50 kg sample to decay to 10 kg? Since 4.8% is 0.048, we have decay as: 50 * (1 - 0.048)^n = 10 0.952^n = 0.2 Typing [URL='https://www.mathcelebrity.com/natlog.php?num=0.952%5En%3D0.2&pl=Calculate']this into our math engine[/URL], we get: n = [B]32.7186 years[/B]