Answer:
Divide
Step-by-step explanation:
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;
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Answer:
a. 720
b. 0.3
Step-by-step explanation:
a.
Three balls are selected at random without replacement.
First ball can be selected in 10 ways
Second ball can be selected in 9 ways
Third ball can be selected in 8 ways
Thus, there are 10×9×8 =720 different ways of selecting three balls.
b.
There are three cases that satisfy this condition
- first ball picked is 5, the others are not
- first ball is not 5, second is 5, third is not
- first and second ball is not five, third ball is 5
Each probabilities are:
Thus, one of the balls selected is the number 5 is then 
Answer:
decrease of 64.3%
Step-by-step explanation:
Percentage change can be calculated from ...
pct change = ((new value)/(original value) -1) × 100%
= (50/140 -1) × 100%
= (-9/14)×100% = -64 2/7% ≈ -64.3%
The price of crude fell about 64.3% in that period.
