Answer:
711.11
Step-by-step explanation:
<h3>Method 1 </h3>
If 777 is decreased by 12%. the number would now be (100% - 12%) 88% of what it was originally
0.88 x 777 = 683.76
683.76 is increased by 4%. 683.76 would now be (100 + 4%) 104% of what it originally was
683.76 x 1.04 = 711.11
<h3>Method 2 </h3>
12% x 777 =
0.12 x 777 = 93.24
777 - 93.24 = 683.76
4% x 683.76 = 27.3504
683.76 + 27.3504 = 711.11
The bones at the time they were discovered when the radioactive element carbon-14 has a half-life of total 5750 years are 10062.5-year-old.
<h3>What is half-lives?</h3>
Half lives is the time interval which is need to decay the atomic nuclei of a radioactive sample.
There is a scientist who determined that the bones from a mastodon had lost 70.3% of their carbon-14. Thus, the fraction remaining is,
f=1-(70.3/100)=1-0.703
f=1-(70.3/100)=0.297
Now the fraction remaining can be given as,
f=(1/2)ⁿ
Here, n is the half life elapsed. Put the value of fraction remaining.
0.297=(1/2)ⁿ
n=1.75
The radioactive element carbon-14 has a half-life of total 5750 years. Thus,
Years=1.75*5750
Years=10062.5
Thus, the bones at the time they were discovered when the radioactive element carbon-14 has a half-life of total 5750 years are 10062.5-year-old.
Learn more about the half lives here;
brainly.com/question/2320811
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