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4 years ago

6

A bag contains 50 marbles, 10 of which are blue, 8 are red, 20 are green, and 12 are purple. Marcie takes a marble out of the ba

g, records the color, and returns it to the bag. How many red marbles should she expect after 500 trials? (5 points)
80

100

120

200
I got 80.

2 answers:

levacccp [35]4 years ago

6 0

You need to work out what fraction of the 50 are red 8\50 are red
Find out how many times 50 goes in 500 500 divided by 50 = 10 Multiply by 8 to get the total number of red
8x10 = 80 red marbles

Lorico [155]4 years ago

5 0

50 total marbles

chance of getting a red marble is 8/50

8/50 = 80/500

Answer is 80

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69 points!!!!!!!!!!!! ANYONE who can answer this please

Sloan [31]

I would either graph these (which would be a easiest) then you would see a line that goes through (0, -2) on the y-axis
And you can either determine the slope from the graph or pick two points above and find the slope.

or spread them out evenly and fill out the missing pieces.

-8. -4

-4. -3

0

4. -1

6. -0.5

8

12. 1

Fill in the middle values and you can put (6,-0.5) on there

What pattern do u see? This way would be pretty hard.

Equation: y=(1/4)x-2

8 0

4 years ago

Read 2 more answers

What is the solution of the equation (x – 5)^2 + 3(x – 5) + 9 = 0? Use u substitution and the quadratic formula to solve.

xz_007 [3.2K]

Answer:

$x = \dfrac{7 \pm 3i\sqrt{3}}{2}$

Step-by-step explanation:

(x – 5)^2 + 3(x – 5) + 9 = 0

This is a quadratic equation in x - 5.

Let u = x - 5, then the quadratic equation becomes:

u^2 + 3u + 9 = 0

We can use the quadratic formula to solve for u.

$u = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

$u = \dfrac{-3 \pm \sqrt{3^2 - 4(1)(9)}}{2(1)}$

$u = \dfrac{-3 \pm \sqrt{9 - 36}}{2}$

$u = \dfrac{-3 \pm \sqrt{-27}}{2}$

$u = \dfrac{-3 \pm 3i\sqrt{3}}{2}$

Since u = x - 5, now we substitute x - 5 for u and solve for x.

$x - 5 = \dfrac{-3 \pm 3i\sqrt{3}}{2}$

$x = \dfrac{-3 \pm 3i\sqrt{3}}{2} + 5$

$x = \dfrac{-3 \pm 3i\sqrt{3}}{2} + \dfrac{10}{2}$

$x = \dfrac{7 \pm 3i\sqrt{3}}{2}$

7 0

3 years ago

A local clothing store sells jeans and shirts. The store makes a $10 profit on the sale of jeans and $3 profit on the sale of th

Zepler [3.9K]

Answer:

An inequality to model the situation is : ( 10 m + 3 n) ≥ 150

Here, m : The number of jeans sold

n : The number of shirts sold.

Step-by-step explanation:

Here, the profit on each sale of jeans = $ 10

The profit on each sale of shirt = $ 3

The profit needed to be made = AT LEAST $150

Now, here: Let us assume the number of jeans sold = m

And, The number of shorts sold =n

So, the profit on m jeans = m x ( Profit on 1 jeans) = m x ( $ 10) = 10 m

So, the profit on n shirts = n x ( Profit on 1 shirt) = n x ( $ 3) = 3 n

⇒ The total profit on m jeans + n shirts = ( 10 m + 3 n)

But, according to the question, the profit should AT LEAST $150.

⇒ TOTAL PROFIT ≥ $ 150

⇒ ( 10 m + 3 n) ≥ 150

Hence, an inequality to model the situation is : ( 10 m + 3 n) ≥ 150

3 0

4 years ago

Researchers obtained a sample of n = 10 children who attended daycare before starting school. The children are given a standardi

attashe74 [19]

Answer:

$t=\frac{55.5-50}{\frac{4.249}{\sqrt{10}}}=4.093$

$p_v =2*P(t_{9}>4.093)=0.00084$

If we compare the p value and the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

We can say that at 5% of significance the true mean is significantly different from 50.

Step-by-step explanation:

Data given and notation

53, 57, 61, 49, 52, 56, 58, 62, 51, 56

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s= \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X))^2}{n-1}}$

And we got:

$\bar X=55.5$ represent the sample mean

$s=4.249$ represent the sample standard deviation

$n=10$ sample size

$\mu_o =50/tex] represent the value that we want to test [tex]\alpha=0.05$ represent the significance level for the hypothesis test (ASSUMED).

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is equal or not to 50 :

Null hypothesis: $\mu = 50$

Alternative hypothesis: $\mu \neq 50$

Since we don't know the population deviation, is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{55.5-50}{\frac{4.249}{\sqrt{10}}}=4.093$

P-value

We need to calculate the degrees of freedom first given by:

$df=n-1=10-1=9$

Since is a two-sided tailed test the p value would given by:

$p_v =2*P(t_{9}>4.093)=0.00084$

Conclusion

If we compare the p value and the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

We can say that at 5% of significance the true mean is significantly different from 50.

6 0

4 years ago

(1 point) let a=⟨−4,−3,2⟩a=⟨−4,−3,2⟩. find a unit vector in the same direction as aa.

sergij07 [2.7K]

A unit vector in the direction of a would be the vector a multiplied by a factor such that the length of vector a is unity.
The magnitude of a is given by:
|a|
=sqrt(4^2+3^2+2^2) [ I got lazy instead of writing (-4)^2+(-3)^2+2^2]
=sqrt(29).

So the univector is a/sqrt(29), or (-4/sqrt(29),-3/sqrt(29), 2/sqrt(29), or simply (-4,-3,2)/sqrt(29).

8 0

3 years ago