What times what equals -7

An ostrich that is 133 inches tall is 18 inches taller than 5 times the height of a kiwi.

PtichkaEL [24]

Answer:

23

Step-by-step explanation:

133 = 18 + 5x

155 = 5x

23 = x

3 0

3 years ago

2. Maria has a garden that is 6 feet by 4 feet. What is the perimeter of Maria's garden?

Anton [14]

Answer:

= 20 ft

Step-by-step explanation:

The perimeter is found by

P = 2(l+w)

= 2(6+4)

=2(10)

= 20 ft

8 0

3 years ago

Find two positive numbers if their ratio is 8:5 and the difference is 150.

natima [27]

Let's call the two numbers x and y. We can write a system of equations to describe the situation:

5x = 8y

x - y = 150

Let's solve the first equation for x:

x = 8y/5

Now we can use substitution to solve the system by plugging 8y/5 in for x in the second equation:

(8y/5) - y = 150

Simplify:

3y/5 = 150

3y = 750

y = 250

If y = 250, then x is:

x = 8(250)/5 = 400

The answer is 250 and 400.

7 0

3 years ago

What numbers round up and down to 600

yaroslaw [1]

The numbers that round up to 600 and have one decimal place are-
599.5
599.6
599.7
599.8
599.9
The numbers that round down to 600 and have one decimal place are-
600.1
600.2
600.3
<span>600.4
As far as numbers with more than one decimal place that round to 600, there is an infinite number. For example, 600.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000</span>0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001 rounds down to 600.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.

7 0

3 years ago

Read 2 more answers

A practice law exam has 100 questions, each with 5 possible choices. A student took the exam and received 13 out of 100.If the s

Cloud [144]

Answer:

$z=\frac{13-20}{4}=-1.75$

Assuming:

H0: $\mu \geq 20$

H1: $\mu$

$p_v = P(Z$

Step-by-step explanation:

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Let X the random variable of interest (number of correct answers in the test), on this case we now that:

$X \sim Binom(n=100, p=0.2)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

We need to check the conditions in order to use the normal approximation.

$np=100*0.2=20 \geq 10$

$n(1-p)=20*(1-0.2)=16 \geq 10$

So we see that we satisfy the conditions and then we can apply the approximation.

If we appply the approximation the new mean and standard deviation are:

$E(X)=np=100*0.2=20$

$\sigma=\sqrt{np(1-p)}=\sqrt{100*0.2(1-0.2)}=4$

So we can approximate the random variable X like this:

$X\sim N(\mu =20, \sigma=4)$

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". The letter $\phi(b)$ is used to denote the cumulative area for a b quantile on the normal standard distribution, or in other words: $\phi(b)=P(z$