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.
Answer: An adult ticket cost $12
A child ticket cost $5
Step-by-step explanation:
Let x represent the price for one adult ticket.
Let y represent the price for one child ticket.
A movie theater sold 4 adult tickets and 7 children's tickets for $83 on Friday. It means that
4x + 7y = 83 - - - - - - - - - - - -1
The next day the theater sold 5 adult tickets and 6 children tickets for $90. It means that
5x + 6y = 90 - - - - - - - - - - - -2
Multiplying equation 1 by 5 and equation 2 by 4, it becomes
20x + 35y = 415
20x + 24y = 360
Subtracting, it becomes
11y = 55
y = 55/11 = 5
Substituting y = 5 into equation 1, it becomes
4x + 7 × 5 = 83
4x + 35 = 83
4x = 83 - 35 = 48
x = 48/4 = 12
Answer: -18
Step-by-step explanation:
3 x -6 = 18
By solving a linear equation, we will see that Victor is 30 years old.
<h3>
How old is Victor now?</h3>
Let's say that Victor is x years old.
We know that 10 years ago, (x - 10), his age was half of what it will be in 10 years (x + 10).
Then we can write the linear equation:
(x - 10) = (x + 10)/2
Now we can solve that equation for x:
2*(x - 10) = x + 10
2x - 20 = x + 10
2x - x = 10 + 20
x = 30
So we conclude that Victor is 30 years old.
If you want to learn more about linear equations:
brainly.com/question/1884491
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