Answer:
18.51 grams.
Step-by-step explanation:
We have been given the decay rate
We have general equation for decay which is:
[tex]y=a\cdot b^t[/tex];[tex]b=1-r[/tex]
Here, we are given with initial sample which is a=300
b=1-13%
And t is 20 years.
We will subatitute the values in the formula we get:
[tex]y=300\cdot (1-\frac{13}{100})^{20}[/tex]
[tex]\Rightarrow y=300(\frac{87}{100})^{20}[/tex]
[tex]\Rightarrow y=300(.87)^{20}[/tex]
After simplification we get y=18.51 grams.
The sample remain will be 18.51 grams.