If 20% of a number is 60 and 55% of the same number is 165, find 75% of that
1 answer:
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The length of material needed for the border is the perimeter of the backyard play area
<h3>How to calculate the length of material needed </h3>The area of the play area is given as:
The area of a trapezoid is calculated using:
Where L1 and L2, are the parallel sides of the trapezoid and H represents the height.
The given parameter is not enough to solve the length of material needed.
So, we make use of the following assumed values.
Assume that the parallel sides are: 25 feet and 31 feet long, respectively.
While the other sides are 10.2 feet and 8.2 feet
The length of material needed would be the sum of the above lengths.
So, we have:
Using the assumed values, the length of material needed for the border is 74.4 feet
Read more about perimeters at:
Given Information:
Mean time to finish 400 meter dash = μ = 65 seconds
Standard deviation to finish 400 meter dash = σ = 2.5 seconds
Confidence level = 95%
Required Information:
95% confidence interval = ?
Answer:
Step-by-step explanation:
In the normal distribution, the empirical rule states approximately 68% of all the data lie within 1 standard deviation from the mean, approximately 95% of all the data lie within 2 standard deviations from the mean and approximately 99.7% of all the data lie within 3 standard deviations from the mean.
The confidence interval for 95% confidence limit is given by
Since approximately 95% of all the data lie within 2 standard deviations from the mean. μ is the mean time Carson takes to finish 400 meter dash and σ is the standard deviation.
Therefore, the 95% confidence interval is between 60 to 70 seconds
What does it mean?
It means that we are 95% confident that the Carson's mean to finish 400 meter dash is within the interval of (60, 70).