Using an exponential function, it is found that it takes 18.6 days for 80% of the material to decay.
The amount of a substance after t days is modeled by:

In which:
- k is the decay rate, as a decimal.
- A(0) is the initial amount.
The half-life is of 8 days, hence
, and this is used to find k.







Hence:

The time it takes for 80% of the material to decay it t for which
, hence:






It takes 18.6 days for 80% of the material to decay.
To learn more about exponential functions, you can take a look at brainly.com/question/24906920
Answer:
$ 2000
Step-by-step explanation:
Find the equation. You find the gradient by using the gradient formula (rise/run)
that would be
1600 - 800 over 40 - 20
800/20
m (gradient) = 40
Hence 40x ...
Answer:
positive fourteen negative nine c
Answer:
a = 10x - 9
Step-by-step explanation:
l = x + 9
w = x - 1
a = l (w)
a = x + 9 (x - 1)
a = x + 9x - 9
a = 10x - 9