Using the mean concept, it is found that we will need 15 more points to bring up his average up to 90%.
The mean of a data-set is the <u>sum of all observations divided by the number of observations</u>.
In this problem:
- In the first 5 observations, total of 21 out of 25 points, hence the mean for these observations is
. - In the next n observations, mean of 1.
Hence, the mean is:

We want the mean to be of 0.9, thus:





3 more testes are need, each worth 5 points, hence, 15 more points are needed to bring up his average up to 90%.
A similar problem is given at brainly.com/question/25323941
I can’t really read it, could you restate it in the comments here?
Y results from something being multiplied by x , and the values are always proportional to one another. Notice that putting these points into a ratio of x-value to y-value results in 1:3 as a simplified version. So, the constant of proportionality is what x is being multiplied by to get y . In this case, it is 3 . PLEASE MARK A THE BRAIN THINGY
Answer: 7 π r² + π r³
Explanation:
1) The general formula for the volumen, V, of a cylinder with radius r and height h is:
V = π r² h
2) Now you have the condition that the height is 7 inches greater than the radius, that is:
h = 7 + r
3) Replace h with its expression
V = π r² (7 + r)
4) Expand the product (use distributive property):
V = π (7r²) + π r³ = 7 π r² + π r³
Answer: 7 π r² + π r³