Question 1168430
The half-life of a substance is 250 years. 
If there were initially 100 grams of the substance, what is the exponential model for the situation?
:
The half-life decay model
A = Ao*2^(-t/h) where
A = remaining amt after t time
Ao = initial amt
t = time of decay
h = half-life of substance
:
In this problem
A = 100*2^(-t/250)
: 
And how much will remain after 500 years?
A = 100*2^(-500/250)
A = 100*2^(-2)
reciprocal gets rid of the negative on the exponent
A = 100*{{{1/2^2)}}}
A = 100*{{{1/4}}}
A = 25 grams remain after 500 years