A music industry researcher wants to estimate, with a 90% confidence level, the proportion of young urban people (ages 21 to 35
1 answer:
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Answer:
% Remaining
And replacing the value t =5.5 hours we got:
% Remaining
Step-by-step explanation:
Previous concepts
The half-life is defined "as the amount of time it takes a given quantity to decrease to half of its initial value. The term is most commonly used in relation to atoms undergoing radioactive decay, but can be used to describe other types of decay, whether exponential or not".
Solution to the problem
The half life model is given by the following expression:
Where A(t) represent the amount after t hours.
represent the initial amount
t the number of hours
h=2.6 hours the half life
And we want to estimate the % after 5.5 hours. On this case we can begin finding the amount after 5.5 hours like this:
Now in order to find the percentage relative to the initial amount w can use the definition of relative change like this:
% Remaining =
We can take common factor and we got:
% Remaining
And replacing the value t =5.5 hours we got:
% Remaining
Answer:
d.
Step-by-step explanation:
The goal of course is to solve for x. Right now there are 2 of them, one on each side of the equals sign, and they are both in exponential positions. We have to get them out of that position. The way we do that is by taking the natural log of both sides. The power rule then says we can move the exponents down in front.
becomes, after following the power rule:
x ln(2) = (x + 1) ln(3). We will distribute on the right side to get
x ln(2) = x ln(3) + 1 ln(3). The goal is to solve for x, so we will get both of them on the same side:
x ln(2) - x ln(3) = ln(3). We can now factor out the common x on the left to get:
x(ln2 - ln3) = ln3. The rule that "undoes" that division is the quotient rule backwards. Before that was a subtraction problem it was a division, so we put it back that way and get:
. We can factor out the ln from the left to simplify a bit:
. Divide both sides by ln(2/3) to get the x all alone:
On your calculator, you will find that this is approximately -2.709