Expand the expression and combine like terms: 2(−14+r)−(−3r−5)

Please help! Giving brainliest

lianna [129]

Answer:

5y^2-12y+21-73/2y+3

6 0

2 years ago

Find a b if a = (4,3) and b =(4,5).<br> a. 31<br> C. (16,15)<br> b. (8,8)<br> d.-1

liq [111]

Your answer will be c

8 0

3 years ago

Read 2 more answers

The walkers traveled 182 miles in 3 1/2 hours. The equation 3.5m=182 can be used to find their mean rate of travel. What is the

Serjik [45]

182 divided byyyy 3.5 =52 miles per hour

6 0

3 years ago

The article "Monte Carlo Simulation—Tool for Better Understanding of LRFD" (J. Structural Engr., 1993: 1586–1599) suggests that

Sedaia [141]

Answer:

a) $P(X$

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

$P(z$

b) $P(X>40)=P(\frac{X-\mu}{\sigma}>\frac{60-\mu}{\sigma})=P(Z>\frac{60-43}{4.5})=P(z>3.78)$

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

$P(z>3.78)=1-P(Z$

c) $z=0.674$

And if we solve for a we got

$a=43 +0.674*4.5=46.033$

So the value of height that separates the bottom 75% of data from the top 25% is 46.033.

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".

Solution to the problem

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

$X \sim N(43,4.5)$

Where $\mu=43$ and $\sigma=4.5$

Part a

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 the normal standard distribution or excel and we got:

$P(z$

Part b

$P(X>40)=P(\frac{X-\mu}{\sigma}>\frac{60-\mu}{\sigma})=P(Z>\frac{60-43}{4.5})=P(z>3.78)$

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

$P(z>3.78)=1-P(Z$

Part c

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

$P(X>a)=0.25$ (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 0.75 of the area on the left and 0.25 of the area on the right it's z=0.674. On this case P(Z<0.674)=0.75 and P(z>0.674)=0.25

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:

$z=0.674$

And if we solve for a we got

$a=43 +0.674*4.5=46.033$

So the value of height that separates the bottom 75% of data from the top 25% is 46.033.

8 0

3 years ago

Please help me round to nearest hundredth

Masteriza [31]

Answer:

(a) 2.27 lb/$

(b) 0.10 mi/min

Step-by-step explanation:

Pounds per dollar is found by dividing pounds by dollars:

(25 lb)/($11.00) ≈ 2.272727... lb/dollar

The digit in the thousandths place is less than 5, so that digit and all digits to its right are dropped when rounding to hundredths.

2.27 pounds per dollar

__

Speed in miles per minute is found by dividing miles by minutes:

(6 mi)/(58 min) ≈ 0.103448... mi/min

Rounding to hundredths is done the same way as above.

0.10 miles per minute

_____

If the digit to the right of the place you're rounding to is 5 or more, then 1 is added in the place you're rounding to when digits to its right are dropped.

5 0

2 years ago