Simplify (-3+5i)(3+5i)
2 answers:
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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
Answer:
0.2348 = 23.48% probability that four will have used the e-ticket check-in kiosk to obtain boarding passes.
Step-by-step explanation:
Hypergeometric distribution:
The probability of x sucesses is given by the following formula:
In which:
x is the number of sucesses.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.
In this question:
Population of 280, which means that
112 use e-ticket check-in kiosk, which means that
Sample of eight passengers means that
Find the approximate hypergeometric probability that four will have used the e-ticket check-in kiosk to obtain boarding passes.
This is P(X = 4). So
0.2348 = 23.48% probability that four will have used the e-ticket check-in kiosk to obtain boarding passes.