A driveway is in the shape of a rectangle 20 feet wide by 25 feet long.

15+9=?(5+3) please help

Tema [17]

Answer:

3

because 15 + 9 = 24

and 3(5 + 3) which is 3 * 5 + 3 * 3 = 15 + 9 = 24

= 24 = 24

Step-by-step explanation:

Please mark me as the brainliest

3 0

3 years ago

A box with a square base and open top must have a volume of 32,000 cm3. find the dimensions of the box that mini- mize the amoun

zmey [24]

Alrighty

squaer base so length=width, nice

v=lwh
but in this case, l=w, so replace l with w
V=w²h

and volume is 32000
32000=w²h

the amount of materials is the surface area
note that there is no top
so
SA=LW+2H(L+W)
L=W so
SA=W²+2H(2W)
SA=W²+4HW

alrighty

we gots
SA=W²+4HW and
32000=W²H

we want to minimize the square foottage
get rid of one of the variables
32000=W²H
solve for H
32000/W²=H
subsitute

SA=W²+4WH
SA=W²+4W(32000/W²)
SA=W²+128000/W

take derivitive to find the minimum
dSA/dW=2W-128000/W²
where does it equal 0?

0=2W-1280000/W²
128000/W²=2W
128000=2W³
64000=W³
40=W

so sub back
32000/W²=H
32000/(40)²=H
32000/(1600)=H
20=H

the box is 20cm height and the width and length are 40cm

7 0

2 years ago

What is the perimeter of JKLM?

Jobisdone [24]

Answer:

45

Step-by-step explanation:

KL = 12 because the triangle is isosceles ( base angles are congruent)

KJ = JM = 12 because the triangle is equilateral ( all angles are equal 60°)

the perimeter is

P = 9 + 12 + 12 +12 = 9 +36 = 45

5 0

2 years ago

It is known that the life of a particular auto transmission follows a normal distribution with mean 72,000 miles and standard de

scoray [572]

Answer:

a) $P(X$

$P(z$

b) $P(X>65000)=P(\frac{X-\mu}{\sigma}>\frac{65000-\mu}{\sigma})=P(Z>\frac{65000-72000}{12000})=P(z>-0.583)$

$P(z>-0.583)=1-P(Z$

c) $P(X>100000)=P(\frac{X-\mu}{\sigma}>\frac{100000-\mu}{\sigma})=P(Z>\frac{100000-72000}{12000})=P(z>2.33)$

$P(z>2.33)=1-P(Z$

Sicne this probability just represent 1% of the data we can consider this value as unusual.

d) $z=1.28$

And if we solve for a we got

$a=72000 +1.28*12000=87360$

So the value of height that separates the bottom 90% of data from the top 10% is 87360.

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the life of a particular auto transmission of a population, and for this case we know the distribution for X is given by:

$X \sim N(72000,12000)$

Where $\mu=72000$ and $\sigma=12000$

We are interested on this probability

$P(X$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X$

And we can find this probability using excel or the normal standard table and we got:

$P(z$

Part b

$P(X>65000)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X>65000)=P(\frac{X-\mu}{\sigma}>\frac{65000-\mu}{\sigma})=P(Z>\frac{65000-72000}{12000})=P(z>-0.583)$

And we can find this probability using the complement rule and excel or the normal standard table and we got:

$P(z>-0.583)=1-P(Z$

Part c

$P(X>100000)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X>100000)=P(\frac{X-\mu}{\sigma}>\frac{100000-\mu}{\sigma})=P(Z>\frac{100000-72000}{12000})=P(z>2.33)$

And we can find this probability using the complement rule and excel or the normal standard table and we got:

$P(z>2.33)=1-P(Z$

Sicne this probability just represent 1% of the data we can consider this value as unusual.

Part d

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.1$ (a)

$P(X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.9 of the area on the left and 0.1 of the area on the right it's z=1.28. On this case P(Z<1.28)=0.9 and P(z>1.28)=0.1

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=1.28$

And if we solve for a we got

$a=72000 +1.28*12000=87360$

So the value of height that separates the bottom 90% of data from the top 10% is 87360.

5 0

2 years ago

A group of friends are at a baseball game and are purchasing souvenirs. Dustin purchased 5 t-shirts and 1 baseball cap, spending

Inessa [10]

Answer:

Shirt-$19

Cap-$24

Step-by-step explanation:

5s+1c=119

1s+1c=43

1c=43-1s

substitute:

5s+(43-1s)=119

5s+43-1s=119

4s=119-43

4s=76

1s=19

substitute:

1c=43-(19)

1c=24

7 0

2 years ago