Can you post this and provide a picture please so I can help you ?
Explanation:
There are 81 girls to every 72 boys in total, which can be represented by 81/72, which put into decimal form, is 1.125. If you then take the number of boys in the group, 16, and multiply it by this number (because the problem states that the ratio is constant) you can find the number of girls in the group.
16*1.125=18
So there are 18 girls in a group with 16 boys.
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Answer:
Step-by-step explanation:
We want to determine a 90% confidence interval for the mean amount of time that teens spend online each week.
Number of sample, n = 41
Mean, u = 43.1 hours
Standard deviation, s = 5.91 hours
For a confidence level of 90%, the corresponding z value is 1.645. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
43.1 ± 1.645 × 5.91/√41
= 43.1 ± 1.645 × 0.923
= 43.1 ± 1.52
The lower end of the confidence interval is 43.1 - 1.52 =41.58
The upper end of the confidence interval is 43.1 + 1.52 =44.62
Therefore, with 90% confidence interval, the mean amount of time that teens spend online each week is between 41.58 and 44.62
4^2+b^2=8^2
16+b^2=64
-16. -16
b^2= 48
Sq root each side
b= sq rt 16 sq rt 3
b= 4 sq rt 3
