-<br> The sum of 2 and x is at least

Solve the system of equations by the substitution method.<br> y = 5x + 6<br> y=9x+7.

joja [24]

Answer:

(-1/4, 19/4)

Step-by-step explanation:

5x+6=9x+7

-4x=1

x= -1/4

y=5(-1/4) +6

y=19/4

3 0

2 years ago

Find three consecutive odd integers such that the sum of the smaller two is three times the largest increased by seven

svlad2 [7]

Let the three odd integers be x - 2, x and x + 2
x - 2 + x = 3(x + 2) + 7
2x - 2 = 3x + 6 + 7
2x - 2 = 3x + 13
3x - 2x = -2 - 13
x = -15

The three consecutive odd integers are -17, -15 and -13.

4 0

3 years ago

The present shown below is a cube. Find the surface area of the present.

Verdich [7]

1350 (dont take my word for it, but i belive this is right)

5 0

3 years ago

g If a random sample of 18 deliveries was selected instead and the standard deviation of these delivery times was found to be 9.

lana [24]

Answer:

We can use the z score formula given by:

$z= \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

If we use this formula we got:

$z=\frac{21-20}{\frac{9.31}{\sqrt{18}}}= 0.456$

$z=\frac{25-20}{\frac{9.31}{\sqrt{18}}}= 2.279$

And using a calculator, excel or the normal standard table and we have that:

$P(0.456$

Step-by-step explanation:

We assume this previous info: It is known that the amounts of time required for room-service delivery at a certain Marriott Hotel are Normally distributed with the average delivery time of 20 minutes.

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 delivery times of a population, and for this case we know the distribution for X is given by:

$X \sim N(20,9.31)$