Pls help me I don't understand
2 answers:
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Answer:
The principal must be = $8991.88
Step-by-step explanation:
Formula for compound interest is:
Where A is the amount after 't' years.
P is the principal amount
n is the number of times interest is compounded each year.
r is the rate of interest.
Here, we are given that:
Amount, A = $15000
Rate of interest = 13 % compounded quarterly i.e. 4 times every year
Number of times, interest is compounded each year, n = 4
Time, t = 4 years.
To find, Principal P = ?
Putting all the given values in the formula to find P.
So, <em>the principal must be = $8991.88</em>
Answer:
8978 grams
Step-by-step explanation:
The equation to find the half-life is:
N(t) = amount after the time <em>t</em>
= initial amount of substance
t = time
It is known that after a half-life there will be twice less of a substance than what it intially was. So, we can get a simplified equation that looks like this, in terms of half-lives.
or more simply
= time of the half-life
We know that = 35,912, t = 14,680, and
=7,340
Plug these into the equation:
Using a calculator we get:
N(t) = 8978
Therefore, after 14,680 years 8,978 grams of thorium will be left.
Hope this helps!! Ask questions if you need!!