Question 1138079
A scientist begins with 250 grams of a radioactive substance.
 After 250 minutes, the sample has decayed to 32 grams. Rounding to five significant digits, 
  what is the exponential equation representing this situation.
:
the radioactive decay formula: A = Ao*2^(-t/h), where
A = amt after t time
Ao = the initial amt
t = time of decay
h = half-life of substance
32 = 250*2^(-250/h)
:
{{{32/250}}} = 2^(-250/h)
:
{{{ln(32/250)}}} = ln(2^(-250/h))
:
-2.02557 = {{{-250/h}}}*.6931
-2.0557h = -250 * .6931
h = {{{(-173.2867)/(-2.0557)}}}
h = 84.0 minutes is the half life of this substance?