Answer: 362,880
Step-by-step explanation: At first glance of the question, it doesn't seem that the order matters, which would make it a question of how many combinations there are. The simple way to look at it is that there are 9 trees and he's planting 8, leaving out 1. Since there are 9 possible trees to leave out, there are 9 possible combinations of which 8 trees to plant.
The formula would be 9!/([9-8]!*8!) = 9
If the question is indeed asking for permutations (order matters), since you are choosing 8 out of 9 the formula would be 9!/(9-8)! = 9!/1! = 9! = 362,880
Solution :
Given :
National mean score of the reading test that is conducted the NAEP = 288
Standard deviation of the score = 38
Therefore, P(X > x) = 0.25
P (Z >
= 0.674)


x = 326.67
Therefore, the highest score that is needed for the students to be in the top of 25 percent among the students those who take the exam.
RemarkI take it that you want to know the ratio of the radii. If this is not correct, leave a comment below my answer.
You could do this by giving the spheres a definite volume, like 1 and 8 and then solve for r for one of them and then use the other sphere to find it's radius. It is not exactly the best way, and if you are going to to a physics class you want to be doing this using cancellation.
Step One Set up the Ratio for the volumes.
Step TwoSetup the equation for V1/V2 using the definition for a sphere. V = 4/3 pi r^3
Step ThreeCancel the 4/3 and pi on the top and bottom of the fractions on the right.
You are left with 1/8 = (r1)^3/ (r2)^3
Step FourTake the cube root of both sides.
cube root 1/8 = 1/2
Cube root of (r1)^3 = r1
Cube root of (r2)^3 = r2
Step FiveAnswer
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