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3 years ago

7z= 21 2x + 3y – z =-2 x=_y=_2= x + 2y + 3z = 9

Mathematics

1 answer:

lbvjy [14]3 years ago

7 0

Answer:

1) 7(3) = 21

Step-by-step explanation:

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IQ scores are normally distributed with a mean of 100 and a standard deviation of 15.

jekas [21]

Using the normal distribution, it is found that 1851 people would have an IQ less than 115.

<h3>Normal Probability Distribution</h3>

The z-score of a measure X of a normally distributed variable with mean $\mu$ and standard deviation $\sigma$ is given by:

$Z = \frac{X - \mu}{\sigma}$

The z-score measures how many standard deviations the measure is above or below the mean.

Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.

The mean and the standard deviation are given, respectively, by:

$\mu = 100, \sigma = 15$

The proportion of IQ scores less than 115 is the p-value of Z when X = 115, hence:

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{115 - 100}{15}$

Z = 1

Z = 1 has a p-value of 0.8413.

Out of 2200 people:

0.8413 x 2200 = 1851.

More can be learned about the normal distribution at brainly.com/question/27643290

#SPJ1

5 0

1 year ago

For the given term, find the binomial raised to the power, whose expansion it came from: 15(5)^2 (-1/2 x) ^4

Elina [12.6K]

Answer:

C. $(5-\frac{1}{2})^6$

Step-by-step explanation:

Given

$15(5)^2(-\frac{1}{2})^4$

Required

Determine which binomial expansion it came from

The first step is to add the powers of he expression in brackets;

$Sum = 2 + 4$

$Sum = 6$

Each term of a binomial expansion are always of the form:

$(a+b)^n = ......+ ^nC_ra^{n-r}b^r+.......$

Where n = the sum above

$n = 6$

Compare $15(5)^2(-\frac{1}{2})^4$ to the above general form of binomial expansion

$(a+b)^n = ......+15(5)^2(-\frac{1}{2})^4+.......$

Substitute 6 for n

$(a+b)^6 = ......+15(5)^2(-\frac{1}{2})^4+.......$

[Next is to solve for a and b]

From the above expression, the power of (5) is 2

Express 2 as 6 - 4

$(a+b)^6 = ......+15(5)^{6-4}(-\frac{1}{2})^4+.......$

By direct comparison of

$(a+b)^n = ......+ ^nC_ra^{n-r}b^r+.......$

and

$(a+b)^6 = ......+15(5)^{6-4}(-\frac{1}{2})^4+.......$

We have;

$^nC_ra^{n-r}b^r= 15(5)^{6-4}(-\frac{1}{2})^4$

Further comparison gives

$^nC_r = 15$

$a^{n-r} =(5)^{6-4}$

$b^r= (-\frac{1}{2})^4$

[Solving for a]

By direct comparison of $a^{n-r} =(5)^{6-4}$

$a = 5$

$n = 6$

$r = 4$

[Solving for b]

By direct comparison of $b^r= (-\frac{1}{2})^4$

$r = 4$

$b = \frac{-1}{2}$

Substitute values for a, b, n and r in

$(a+b)^n = ......+ ^nC_ra^{n-r}b^r+.......$

$(5+\frac{-1}{2})^6 = ......+ ^6C_4(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+ ^6C_4(5)^{6-4}(\frac{-1}{2})^4+.......$

Solve for $^6C_4$

$(5-\frac{1}{2})^6 = ......+ \frac{6!}{(6-4)!4!)}*(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+ \frac{6!}{2!!4!}*(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+ \frac{6*5*4!}{2*1*!4!}*(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+ \frac{6*5}{2*1}*(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+ \frac{30}{2}*(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+15*(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+15(5)^{6-4}(\frac{-1}{2})^4+.......$

$(5-\frac{1}{2})^6 = ......+15(5)^2(\frac{-1}{2})^4+.......$

Check the list of options for the expression on the left hand side

The correct answer is $(5-\frac{1}{2})^6$

3 0

3 years ago

What is the height of a projectile in 4 seconds if its initial height is 125 ft and it has a velocity of 300 ft per second? 972

andre [41]

Answer:

B. 1069 feet

Step-by-step explanation:

$d=v_ot+\dfrac{1}{2}at^2 \\\\d=(300)(4)+\dfrac{1}{2}(-32)(4)^2 \\\\d=1200-256=944$

Adding the initial 125 feet to this, you get a total height of 1069 feet. Hope this helps!

4 0

3 years ago

On a number line, the directed line segment from Q to S has endpoints Q at -2 and S at 6. Point R partitions the directed line s

Alona [7]

The answer is 14/5, there ya go

7 0

3 years ago

Read 2 more answers

Show your work: Express 160 pounds (lbs) in kilograms (kg). Round to the nearest hundredths.

andrew-mc [135]

Answer:

160 lbs = 72.57kg

Step-by-step explanation:

This can be solved as a rule of three problem.

In a rule of three problem, the first step is identifying the measures and how they are related, if their relationship is direct of inverse.

When the relationship between the measures is direct, as the value of one measure increases, the value of the other measure is going to increase too.

When the relationship between the measures is inverse, as the value of one measure increases, the value of the other measure will decrease.

Unit conversion problems, like this one, is an example of a direct relationship between measures.

Each lb has 0.45kg. How many kg are there in 160lbs. So:

1lb - 0.45kg

160 lbs - xkg

$x = 0.45*160$

$x = 72.57$ kg

160 lbs = 72.57kg

4 0

3 years ago