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3 years ago

HELP NEEDED!!! WILL GIVE 5 STARS!

1 answer:

3 0

270=2b + a
420=2a + 3c (you have to use trial and error for this)

B = 120
A = 30
C = 120

Just to check
270 = (2x120) + 30
420 = (2x30) + (3x120)

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A certain standardized test's math scores have a bell-shaped distribution with a mean of 530 and a standard deviation of 119. Co

kumpel [21]

Answer:

a) 68.2%

b) 31.8%

c) 2.3%

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 530

Standard Deviation, σ = 119

We are given that the distribution of math scores is a bell shaped distribution that is a normal distribution.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

a) P(test scores is between 411 and 649)

$P(411 \leq x \leq 649)\\\\= P(\displaystyle\frac{411 - 530}{119} \leq z \leq \displaystyle\frac{649-530}{119})\\\\= P(-1 \leq z \leq 1)\\\\= P(z \leq 1) - P(z < -1)\\= 0.841 - 0.159 = 0.682 = 68.2\%$

b) P(scores is less than 411 or greater than 649)

$P(x < 411 < x, x > 649)\\=1 = P(411 \leq x \leq 649)\\=1 - 0.682\\=0.318 = 31.8\%$

c) P(score greater than 768)

P(x > 768)

$P( x > 768) = P( z > \displaystyle\frac{768 - 530}{119}) = P(z > 2)$

$= 1 - P(z \leq 2)$

Calculation the value from standard normal z table, we have,

$P(x > 768) = 1 -0.977 = 0.023 = 2.3\%$

5 0

4 years ago

In a horse race with 5 horses, you make a bet by predicting the ranking of all 5 horses. Suppose you place your bet at random. W

lapo4ka [179]

Answer:

P( top two horses are predicted incorrectly in incorrect order)

= $\frac{1}{2}$

Step-by-step explanation:

In the horse race the outcome can be predicted in 5! = 120 ways.

Now suppose the top two horses were predicted incorrectly in incorrect order. Now, the top horse can be predicted incorrectly in 4 ways.

Suppose the top horse was predicted to be in k-th position where k = 2, 3 ,4,5

so the second horse can be predicted to be in place from 1 to (k - 1)

So, the top two horses can be predicted incorrectly in incorrect order

in $\sum_{k =2}^{5}(k - 1)$ = 10 ways

and for each prediction of the two the remaining horses may be predicted in 3! = 6 ways.

Hence ,

P( top two horses are predicted incorrectly in incorrect order)

= $\frac{6 \times 10}{120}$

= $\frac{1}{2}$

8 0

3 years ago

Lina has a total of 72 blue and red marbles in a box. The probability of choosing a blue marble at random from the box is 4/9

blsea [12.9K]

Answer:

Step-by-step explanation:

probability of getting blue ball is 4/9

total cases = 72

i.e number of blue ball 32

number of red vall is 40

so extra 28 is added

3 0

3 years ago

Given f(x) and g(x) are inverse functions. If f(-2)=1 then g(1)=-2 True False

PilotLPTM [1.2K]

True.

The y-axis of the f(x) must equal to the x-axis of g(x)

The x-axis of the f(x) must equal to the y-axis of g(x)

3 0

3 years ago

Read 2 more answers

The exponential function f(x) = 2^x undergoes two transformations to

Eddi Din [679]

Option A: It is vertically stretched

Option B: it is shifted down

Solution:

The exponential function $f(x)=2^{x}$ undergoes two transformations to $g(x)=5 \cdot 2^{x}-3$ .

To determine how the graph changes:

Consider the given exponential function $f(x)=2^{x}$ .

Let y = f(x)

Vertically compressed or stretched:

A vertically compression (stretched) of a graph is compressing the graph toward x-axis.

• if k > 1 , then the graph y = k• f(x) , the graph will be vertically stretched by multiplying each y coordinate by k.

• if 0 < k < 1 if 0 < k < 1 , the graph is f(x) vertically shrunk (or compressed) by multiplying each of its y-coordinates by k.

• if k should be negative, the vertical stretch or shrink is followed by a reflection across the x-axis.

Here, k = 5

So the graph will be vertically stretched.

Also, Adding 3 to the graph will move the graph 3 units down so, the graph is shifted down.

So, The graph is shifted down.

Hence option A and option B is the correct answer.

5 0

3 years ago