Somebody help with both questions

What is the solution to the inequality + 4 ≤ 0?

velikii [3]

<span>y + 4 ≤ 0
----------------------
Subtract 4 from each side
</span><span>y + 4 - 4 ≤ 0 - 4
</span>y ≤ -4

y ≤ -4 is the answer

3 0

3 years ago

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A box contains 5 red and 5 blue marbles. Two marbles are withdrawn randomly. If they are the same color, then you win $1.10; if

topjm [15]

Answer:

a) The expected value is $\frac{-1}{15}$

b) The variance is $\frac{49}{45}$

Step-by-step explanation:

We can assume that both marbles are withdrawn at the same time. We will define the probability as follows

#events of interest/total number of events.

We have 10 marbles in total. The number of different ways in which we can withdrawn 2 marbles out of 10 is $\binom{10}{2}$ .

Consider the case in which we choose two of the same color. That is, out of 5, we pick 2. The different ways of choosing 2 out of 5 is $\binom{5}{2}$ . Since we have 2 colors, we can either choose 2 of them blue or 2 of the red, so the total number of ways of choosing is just the double.

Consider the case in which we choose one of each color. Then, out of 5 we pick 1. So, the total number of ways in which we pick 1 of each color is $\binom{5}{1}\cdot \binom{5}{1}$ . So, we define the following probabilities.

Probability of winning: $\frac{2\binom{5}{2}}{\binom{10}{2}}= \frac{4}{9}$

Probability of losing $\frac{(\binom{5}{1})^2}{\binom{10}{2}}\frac{5}{9}$

Let X be the expected value of the amount you can win. Then,

E(X) = 1.10*probability of winning - 1 probability of losing = $1.10\cdot \frac{4}{9}-\frac{5}{9}=\frac{-1}{15}$

Consider the expected value of the square of the amount you can win, Then

E(X^2) = (1.10^2)*probability of winning + probability of losing = $1.10^2\cdot \frac{4}{9}+\frac{5}{9}=\frac{82}{75}$

We will use the following formula

$Var(X) = E(X^2)-E(X)^2$

Thus

Var(X) = $\frac{82}{75}-(\frac{-1}{15})^2 = \frac{49}{45}$

7 0

3 years ago

In a survey from 1998, 449 teenagers were surveyed about the music that they listen to. Of these teenagers, 129 of them said tha

marshall27 [118]

Answer:

H0:p1=p2; Ha:p1≠p2, which is a two-tailed test.

Step-by-step explanation:

We formulate our hypotheses as

H0:p1=p2; Ha:p1≠p2, which is a two-tailed test.

Supposing the probability or proportion of the first survey is equal to the probability or proportion of the second survey. This will be the null hypothesis and the alternative hypotheses would be that these two proportions or probabilities are unequal.

This is a two tailed test.

6 0

3 years ago

6. What is the tens' digit of the largest 4-digit even number which uses each of the digits 5, 7, 8, and 9 exactly once?

denpristay [2]

Answer:

B)

Step-by-step explanation:

8 is even number which uses each of the digits exactly once.

5 0

3 years ago

mark bought 168 meters of fencing to enclose an area of pasture for his sheep. he plans to use all of the fencing to make a rect

Anika [276]

The two long sides are 63meters and the shorter sides are 21meters.

7 0

3 years ago

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