Answer: 2.66 × 10⁻¹³
<u>Step-by-step explanation:</u>
First, use the decay formula
where
- A is the final amount (amount left)
- A₀ is the initial amount (amount you started with)
- k is the rate of decay (you need to solve for this)
- t is the time
Given:
- A = 1/2(300) = 150
- A₀ = 300
- k = unknown
- t = 28.8

Next, input the k-value and the new t-value to solve for A.
- A = unknown
- A₀ = 300
- k = -0.0240676
- t = 1440

Using the t-distribution to build the 99% confidence interval, it is found that:
- The margin of error is of 3.64.
- The 99% confidence interval for the population mean is (19.36, 26.64).
<h3>What is a t-distribution confidence interval?</h3>
The confidence interval is:

In which:
is the sample mean.
- s is the standard deviation for the sample.
The critical value, using a t-distribution calculator, for a two-tailed 95% confidence interval, with 21 - 1 = 20 df, is t = 2.086.
The other parameters are given as follows:

The margin of error is given by:

Hence the bounds of the interval are:


The 99% confidence interval for the population mean is (19.36, 26.64).
More can be learned about the t-distribution at brainly.com/question/16162795
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Your answer is c, hope this helps, ask me any questions if needed+
D for the same reason percents
The fraction is 1/15 and the decimal is 1.15