A 13 foot ladder is leaning against the wall of a house. The ladder is 5 feet away from th
1 answer:
You might be interested in
Answer:
- <u>59.0891 g (rounded to 4 decimal places)</u>
Explanation:
<em>Half-life time</em> of a radioactive substance is the time for half of the substance to decay.
Thus, the amount of the radioactive substance that remains after a number n of half-lives is given by:
Where:
- A is the amount that remains of the substance after n half-lives have elapses, and
- A₀ is the starting amount of the substance.
In this problem, you have that the half-live for your sample (polonium-210) is 138 days and the number of days elapsed is 330 days. Thus, the number of half-lives elapsed is:
- 330 days / 138 days = 2.3913
Therefore, the amount of polonium-210 that will be left in 330 days is:
Answer:
91%
Step-by-step explanation:
We can use the formula
- "is" is 90
- "of" is 99
- "percent" is what we are solving for so we will denote it as x
Substituting in our values we get
- We will need to cross multiply here to get (90)(100) = (x%)(99)
- This simplifies to 9000 = 99x%
- Dividing by 99 on both sides we get 90.9% → x = 91%