Answer:
The original number was 54.5.
Step-by-step explanation:
If a number is increased by 2.8%, then it is 102.8% of it's original number.
In mathematics, "of" in virtually all cases means "multiplied by".
Therefore, we do the opposite:
1. Convert to a decimal.
102.8% = 1.028
2. Divide by the decimal.

3. Round it to the nearest tenth.
54.47 rounds to 54.5.
Answer:
4096.50, 4,096.50, $4,096.50, or $4096.5
Step-by-step explanation:
The 90% confidence interval for the population mean is 78.1905<x<81.8095
<h3>Confidence interval</h3>
The formula for calculating the confidence interval is expressed as:
CI = x ± z*s/√n
Given the following parameters
mean "x" = 80
z = 1.645
s = 5.5
n = 25
Substitute
CI = 80 ± 1.645*5.5/√25
CI = 80 ± 1.8095
CI = {78.1905, 81.8095}
Hence the 90% confidence interval for the population mean is 78.1905<x<81.8095
Learn more on confidence interval here: brainly.com/question/2141785
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