Question

HELP ME I WILL GIVE YOU BRAINLIEST

Answer 1

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):

$A(t)=A_{0} (1-r)^t$

Where:

$A_{0}$ 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:

$A(t)=A_{0} (1-r)^t\\A(18)=820*(1-0.268)^18\\A(18)=820*(0.732)^18\\\\A(18)=2.985grams$

Which can be rounded to 3.0 grams

Answer 2

Answer:

3 grams

Step-by-step explanation:

1.  820*26.8%=219.76

820-219.76=600.24

2.  600.24*26.8%=160.86432

600.24-160.86432=439.37568

3.  439.37568*26.8%=117.752682

439.37568-117.752682=321.622998

4.  321.622998*26.8%=86.1949635

321.622998-86.1949635=235.428034

5.  235.428034*26.8=63.0947131

235.428034-63.0947131=172.333321

6.  172.333321*26.8%=46.18533

172.333321-46.18533=126.147991

7.  126.147991*26.8%=33.8076616

126.147991-33.8076616=92.3403294

8.  92.3403294*26.8%=24.7472083

92.3403294-24.7472083=67.5931211

9.  67.5931211*26.8%=18.1149565

67.5931211-18.1149565=49.4781646

10.  49.4781646*26.8%=13.2601481

49.4781646-13.2601481=36.2180165

11.  36.2180165*26.8%=9.70642842

36.2180165-9.70642842=26.5115881

12.  26.5115881*26.8%

26.5115881-7.10510561=19.4064825

13.  19.4064825*26.8%=5.20093731

19.4064825-5.20093731=14.2055452

14.  14.2055452*26.8%=3.80708611

14.2055452-3.80708611=10.3984591

15.  10.3984591*26.8%

10.3984591-2.78678704=7.61167206

16.  7.61167206*26.8%

7.61167206-2.03992811=5.57174395

17.  5.57174395*26.8%=1.49322738

5.57174395-1.49322738=4.07851657

18.  4.07851657*26.8%=1.09304244

4.07851657-1.09304244=2.98547413

2.98547413

3

Too much ;-;