Answer:
3.0 grams of the element are left after 18 minutes
Step-by-step explanation:
Recall that an exponential decay that can be studied with the following formula for the amount of material (A) as a function of time (t):
[tex]A(t)=A_0(1-r)^t[/tex]
where:
[tex]A_0[/tex] is the starting amount of the substance (in our case 820 grams)
r is the rate of decay (which in our case given as 26.8% can be written in decimal form as 0.268
and t is the time in minutes (in our case t = 18 minutes)
Then we have:
[tex]A(t)=A_0(1-r)^t\\A(18)=820*(1-0.268)^18\\A(18)=820*(0.732)^18\\\\A(18)=2.985\,grams[/tex]
which can be rounded to 3.0 grams
Answer: 3.0
Step-by-step explanation:
a=820
r= rate= 26.8%=0.268
b=1-r=1-0.268=0.732
y=820(0.732)^18
y=2.985474
y=3
