Here is dependence between scores and x-values:

where
is the mean,
is standard deviation and i changes from 1 to 2.
1. When i=1,
then

2. When i=2,
then

Now solve the system of equations:


Subtract first equation from the second:

Then

Answer: the mean is 62, the standard deviation is 20.
Answer: 8.94
Step-by-step explanation:
Answer:
36 minutes
Step-by-step explanation:
Let the productivity of slower computer is x bits/min
That means Slower computer in 45 minutes sends x*45 bits= company's email
Let the productivity of faster computer is y bits/min
That means that working together slower and faster computers send
x*20+y*20= company's email or
x*20+y*20=x*45
x*25=y*20
y/x=25/20= 1,25
That means that faster computer sends the mails 1.25 times faster than slower computer
So faster computer will need in 1.25 times lees time than slower computer to do this job
45:1.25 =36 min
37 is the correct answer
4•37+2=150
In order to find the smallest amount of cardboard needed, you need to find the total surface area of the rectangular prism.
Therefore, you need to understand how the cans are positioned in order to find the dimensions of the boxes: two layers of cans mean that the height is
h = 2 · 5 = 10 in
The other two dimensions depend on how many rows of how many cans you decide to place, the possibilities are 1×12, 2×6, 3×4, 4×3, 6×2, 12×1.
The smallest box possible will be the one in which the cans are placed 3×4 (or 4×3), therefore the dimensions will be:
a = 3 · 3 = 9in
b = 3 <span>· 4 = 12in
Now, you can calculate the total surface area:
A = 2</span>·(a·b + a·h + b·h)
= 2·(9·12 + 9·10 + 12·10)
= 2·(108 + 90 + 120)
= 2·318
= 636in²
Hence, the smallest amount of carboard needed for the boxes is 636 square inches.