Answer:
ok
Step-by-step explanation:
A = (a+b)/2
2*A = 2*(a+b)/2 ... multiply both sides by 2
2A = a+b
2A-a = a+b-a ... subtract 'a' from both sides to isolate b
2A-a = b
b = 2A-a
Answer: b = 2A-a
Answer
Find out the how much did each student recieve .
To prove
Let us assume that each student earned in the bake sell be x .
As given
Three students earned $48.76 at the bake sell.
The students split the earnings evenly i.e earning is divided into three equal parts .
Than the equation becomes

Solving the above
x = $16.25(approx)
Therefore the each student recieve $16.25(approx) .
Hence proved
Answer:

Step-by-step explanation:
The terms of this sum make the arithmetic sequence.
The fomula of a sum of <em>n</em> terms of an arithmetic sequence:
![S_n=\dfrac{[2a_1+(n-1)d]\cdot n}{2}](https://tex.z-dn.net/?f=S_n%3D%5Cdfrac%7B%5B2a_1%2B%28n-1%29d%5D%5Ccdot%20n%7D%7B2%7D)
We have

Substitute:
![S_{50}=\dfrac{[2\cdot2+(50-1)\cdot15]\cdot50}{2}=(4+49\cdot15)\cdot25=(4+735)\cdot25\\\\=739\cdot25=18,475](https://tex.z-dn.net/?f=S_%7B50%7D%3D%5Cdfrac%7B%5B2%5Ccdot2%2B%2850-1%29%5Ccdot15%5D%5Ccdot50%7D%7B2%7D%3D%284%2B49%5Ccdot15%29%5Ccdot25%3D%284%2B735%29%5Ccdot25%5C%5C%5C%5C%3D739%5Ccdot25%3D18%2C475)
Answer:
2119 students use the computer for more than 40 minutes. This number is higher than the threshold estabilished of 2000, so yes, the computer center should purchase the new computers.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

The first step to solve this question is finding the proportion of students which use the computer more than 40 minutes, which is 1 subtracted by the pvalue of Z when X = 40. So



has a pvalue of 0.7881.
1 - 0.7881 = 0.2119
So 21.19% of the students use the computer for longer than 40 minutes.
Out of 10000
0.2119*10000 = 2119
2119 students use the computer for more than 40 minutes. This number is higher than the threshold estabilished of 2000, so yes, the computer center should purchase the new computers.