Answer:
4 different ways
Step-by-step explanation:
Total number of children = 4
Distribution of the 4 children :
Number of boys = 3 ; Number of girls = 1
Boy = B ; Girl = G
Possible combinations :
BBBG ; GBBB ; BBGB ; BGBB
From the pascal triangle number of e; number of outcomes = 2
Having exactly 3 boys and 1 girl
Hence, of any of the 4 four total children, 3 must be boys and 1 girl ;
Answer:
7 reservoirs
Step-by-step explanation:
1 yards = 3 feet => 3.5 yards = 10.5 feet
To determine how many numbers of reservoirs to reserve 90000, we first need to determine the capacity of each reservoirs (how much liquid one reservoir can contain) - which is equal to the volume.
The formula to calculate the volume of a circular cylinder is:
- <em>Volume of cylinder = Area of base x Height </em>
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The base of this cylinder is a circle with radius equal to 4 feet. (
)
=> The are of the base is =
= 3.14 x 4^2 = 50.24 feet square
=> The volume of cylinder = Area of base x Height
=> The volume of one cylinder = 50.24 x 10.5 = 527.52 Cubic foot
We have: 1 cubic foot = 28.317 liters
=> 1 liter = 1/28.317 cubic foot
=> 90000 liters equal to: 90000/28.317 = 3,178.303 cubic foot
The number of reservoirs needed to contain 90000 liters of liquid is:
3,178.303/527.52 = 6.025
=> So that it needs 7 reservoirs to store all 90000 liters of liquid.
Answer:
The answer is the length of time in one time interval
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Answer:
Step-by-step explanation:
We want to determine a 90% confidence interval for the mean amount of time that teens spend online each week.
Number of sample, n = 41
Mean, u = 43.1 hours
Standard deviation, s = 5.91 hours
For a confidence level of 90%, the corresponding z value is 1.645. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
43.1 ± 1.645 × 5.91/√41
= 43.1 ± 1.645 × 0.923
= 43.1 ± 1.52
The lower end of the confidence interval is 43.1 - 1.52 =41.58
The upper end of the confidence interval is 43.1 + 1.52 =44.62
Therefore, with 90% confidence interval, the mean amount of time that teens spend online each week is between 41.58 and 44.62