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3 years ago

What is the answer to - 4-(- 4)

Mathematics

1 answer:

ANEK [815]3 years ago

6 0

Answer:

Step-by-step explanation:

-4-(-4)

see how there is a minus sign and a negative

this is known as a double negative

double negative's always = a plus sign

therefore the problem is really read as

-4+4

which equals 0

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Diano4ka-milaya [45]

Answer:

Step-by-step explanation:

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3 years ago

1 point) As reported in "Runner's World" magazine, the times of the finishers in the New York City 10 km run are normally distri

BigorU [14]

Answer:

(a) E (X) = 61 and SD (X) = 9

(b) E (Z) = 0 and SD (Z) = 1

Step-by-step explanation:

The time of the finishers in the New York City 10 km run are normally distributed with a mean,μ = 61 minutes and a standard deviation, σ = 9 minutes.

(a)

The random variable X is defined as the finishing time for the finishers.

Then the expected value of X is:

E (X) = 61 minutes

The variance of the random variable X is:

V (X) = (9 minutes)²

Then the standard deviation of the random variable X is:

SD (X) = 9 minutes

(b)

The random variable Z is the standardized form of the random variable X.

It is defined as: $Z=\frac{X-\mu}{\sigma}$

Compute the expected value of Z as follows:

$E(Z)=E[\frac{X-\mu}{\sigma}]\\=\frac{E(X)-\mu}{\sigma}\\=\frac{61-61}{9}\\=0$

The mean of Z is 0.

Compute the variance of Z as follows:

$V(Z)=V[\frac{X-\mu}{\sigma}]\\=\frac{V(X)+V(\mu)}{\sigma^{2}}\\=\frac{V(X)}{\sigma^{2}}\\=\frac{9^{2}}{9^{2}}\\=1$

The variance of Z is 1.

So the standard deviation is 1.

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3 years ago

what is the volume of a rainwater collection tank that is shaped like a cylinder with a diameter of 10 cm when using 3.14 for<im

oksano4ka [1.4K]

The equation to find the volume of a cylinder is V= $\pi$ ×r²×h. To find r you just divide the diameter which is 10 by 2 so r is 5. Just plug everything in and solve, V= $\pi$ ×5²×243.84. You should get V≈19,151.15

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4 years ago

Here it is, I hope it shows up clearer

Dafna1 [17]

just answering so no links can answer

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2 years ago

There is a machine with toys in it that each cost between cents and dollars, with each toy being cents more expensive than the n

Tju [1.3M]

The required probability that sam has to get change for the 10-dollar bill before he can buy his favorite toy is 6/7.

<h3>What is probability?</h3>

The fraction of favorable outcomes to the total number of outcomes of an event is said to be its probability of occurrence.

P(N) = n(N)/n(S)

N- an event; S- total outcomes;

<h3>Calculation:</h3>

It is given that,

n(s) = 8

So, the probability of buying the favorite toy first is 1/8

and the probability of buying the favorite toy a second is (1/8)(1/7) = 1/56

For these probabilities, Sam won't need to change the 10-dollar bill.

Then,

The probability that Sam has to get change for the 10-dollar bill before he can buy his favorite toy is

= 1 - Probability that he won't need to change

= 1 - (1/8 + 1/56)

= 1 - 1/7

= 6/7

Learn more about probability here:

brainly.com/question/24756209

#SPJ4

Disclaimer: The given question on the portal is incomplete. Here is the complete question.

Question: There is a machine with 8 toys in it that each costs between 25 cents and 2 dollars, with each toy being 25 cents more expensive than the next most expensive one. Each time Sam presses the big red button on the machine, the machine randomly selects one of the remaining toys and gives Sam the option to buy it. If Sam has enough money, he will buy the toy, the red button will light up again, and he can repeat the process. If Sam has 8 quarters and a ten-dollar bill and the machine only accepts quarters, what is the probability that Sam has to get change for the 10-dollar bill before he can buy his favorite toy- the one that costs $1.75? Express your answer as a common fraction.

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1 year ago