Answer:
The rate of decrease is 8%
Step-by-step explanation:
we know that
The general equation for the radioactive decay can be written as:
[tex]a=a_0(1-r)^t[/tex]
where
a is the amount in kilograms after time t.
a_0 is the original amount of the substance or y-intercept of the function
r is the decay rate, written in decimals.
t is the time
In this problem we have
[tex]a=0.65(0.92)^t[/tex]
so
[tex]a_0=0.65\\(1-r)=0.92[/tex]
solve for r
[tex]r=1-0.92=0.08[/tex]
Convert to percentage
[tex]0.08(100)=8\%[/tex]
