The Normal probability distribution function is left-skewed, right-skewed, or symmetric depending on the values of the variance and the standard deviation might the mean of a probability distribution for a discrete random variable be less than (or greater than) the average of possible values.
A probability distribution is a mathematical function that describes the probabilities of different possible values of a variable. Probability distributions are often represented using graphs or probability tables.
Probability distributions are called discrete probability distributions, and the set of outcomes is inherently discrete. For example, if you roll a die, all possible outcomes are discrete and you get a large number of outcomes. Also called probability mass function.
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Answer:
12/40 (simplified = 3/10)
Step-by-step explanation:
2 x 6 = 12
5 x 8 = 40
Answer: option <span>D) y=x, x-axis, y=x, y-axis</span>.
I first thought it was the option C) and I tried with it but it was wrong. This is how I dit it.
Option C step by step:
<span>1) Reflection over the x - axis => point with coordinates (a,b) is transformed into point with coordinates (a, -b)
2) Reflection over the line y = x => point with coordinates (a, -b) is transformed into point with coordinates (-b,a)
3) New feflection over the x - axis => (-b,a) transforms into (-b, -a)
4) New reflection over the line y = x => (-b,-a) transforms into (-a,-b)
Which shows it is not the option C).
Then I probed with option D. Step by step:
1) Reflection over the line y = x => (a,b) → (b,a)
2) Reflection over the x-axis => (b,a) → (b,-a)
3) Reflection over the line y = x => (b,-a) → (-a,b)
4) Reflection over the y-axis => (-a,b) → (a,b).
So, this set of reflections, given by the option D) transforms any point into itself, which proofs that the option D) is the right answer.
</span>
Answer:
2 km/h
Step-by-step explanation:
Let x represent the speed of the river current, t₁ be the time spent rowing against the current and t₂ be the time spent rowing with the current.
Since the speed of the still water = 20 km/h.
The speed of rowing against the current = (20 - x)
The speed of rowing with the current = (20 + x)
We know that velocity = distance / time. Hence time = distance / velocity
t₁ = 36 / (20 - x)
t₂ = 22 / (20 + x)
but t₁ + t₂ = 3 hours
Therefore:
3 = 36 / (20 - x) + 22 / (20 + x)
multiply through by 400 - x²
3(400 - x²) = 36(20 + x) + 22(20 - x)
1200 - 3x² = 720 + 36x + 440 - 22x
3x² + 14x -40 = 0
This gives x = -6.7 or x = 2
x cannot be negative therefore x = 2 km/h
The speed of the river current is 2 km/h
