Becky is so excited to go play basketball with all of her friends at the gym. They decided to play a game. In the game, they wil
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Answer:
The wood was cut approximately 8679 years ago.
Step-by-step explanation:
At first we assume that examination occured in 2020. The decay of radioactive isotopes are represented by the following ordinary differential equation:
(Eq. 1)
Where:
- First derivative of mass in time, measured in miligrams per year.
- Time constant, measured in years.
- Mass of the radioactive isotope, measured in miligrams.
Now we obtain the solution of this differential equation:
(Eq. 2)
Where:
- Initial mass of isotope, measured in miligrams.
- Time, measured in years.
And time is cleared within the equation:
Then, time constant can be found as a function of half-life:
(Eq. 3)
If we know that and
, then:
The wood was cut approximately 8679 years ago.
Answer:
The minimum percentage of the commuters in the city has a commute time within 2 standard deviations of the mean is 75%.
Step-by-step explanation:
We have no information about the shape of the distribution, so we use Chebyshev's Theorem to solve this question.
Chebyshev Theorem
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
An in general terms, the percentage of measures within k standard deviations of the mean is given by .
Applying the Theorem
The minimum percentage of the commuters in the city has a commute time within 2 standard deviations of the mean is 75%.