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3 years ago

Write words to match the expression 36÷4

2 answers:

8 0

Divide 36 by 4.

OR

Molly has 36 potatoes and 3 other friends. How many potatoes can she divide equally between them and her?

Gala2k [10]3 years ago

7 0

There are 36 people at a party and Jack gives each person equally 4 pieces of cake.

Also 36 ÷4 =9

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on a SOL, a test that had 60 questions. how many questions could've you gotten wrong to have a passing grade?

iren [92.7K]

I think its 45 or 55

7 0

3 years ago

Read 2 more answers

how can u stand applying math to every thing doesn't it make every thing repetitive and why does every thing need a pattern does

Dominik [7]

Because math sucks like really really sucks

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3 years ago

Our faucet is broken, and a plumber has been called. The arrival time of the plumber is uniformly distributed between 1pm and 7p

Ymorist [56]

Answer:

$E(A+B) = E(A)+E(B)=4+0.5 =4.5 hours$

$Var(A+B)= Var(A)+Var(B)=3+0.25 hours^2=3.25 hours^2$

Step-by-step explanation:

Let A the random variable that represent "The arrival time of the plumber ". And we know that the distribution of A is given by:

$A\sim Uniform(1 ,7)$

And let B the random variable that represent "The time required to fix the broken faucet". And we know the distribution of B, given by:

$B\sim Exp(\lambda=\frac{1}{30 min})$

Supposing that the two times are independent, find the expected value and the variance of the time at which the plumber completes the project.

So we are interested on the expected value of A+B, like this

$E(A +B)$

Since the two random variables are assumed independent, then we have this

$E(A+B) = E(A)+E(B)$

So we can find the individual expected values for each distribution and then we can add it.

For ths uniform distribution the expected value is given by $E(X) =\frac{a+b}{2}$ where X is the random variable, and a,b represent the limits for the distribution. If we apply this for our case we got:

$E(A)=\frac{1+7}{2}=4 hours$

The expected value for the exponential distirbution is given by :

$E(X)= \int_{0}^\infty x \lambda e^{-\lambda x} dx$

If we use the substitution $y=\lambda x$ we have this:

$E(X)=\frac{1}{\lambda} \int_{0}^\infty y e^{-\lambda y} dy =\frac{1}{\lambda}$

Where X represent the random variable and $\lambda$ the parameter. If we apply this formula to our case we got:

$E(B) =\frac{1}{\lambda}=\frac{1}{\frac{1}{30}}=30min$

We can convert this into hours and we got E(B) =0.5 hours, and then we can find:

$E(A+B) = E(A)+E(B)=4+0.5 =4.5 hours$

And in order to find the variance for the random variable A+B we can find the individual variances:

$Var(A)= \frac{(b-a)^2}{12}=\frac{(7-1)^2}{12}=3 hours^2$

$Var(B) =\frac{1}{\lambda^2}=\frac{1}{(\frac{1}{30})^2}=900 min^2 x\frac{1hr^2}{3600 min^2}=0.25 hours^2$

We have the following property:

$Var(X+Y)= Var(X)+Var(Y) +2 Cov(X,Y)$

Since we have independnet variable the Cov(A,B)=0, so then:

$Var(A+B)= Var(A)+Var(B)=3+0.25 hours^2=3.25 hours^2$

3 0

3 years ago

Which complex number does NOT fall within the shaded region in this graph?

avanturin [10]

In order to find which is the answer, we will go step-by-step. Numbers that are not followed by I are drawn on the Real Axis and the other ones are drawn on the Imaginary Axis. You go first on the Real Axis and then on the Imaginary Axis and intersect those 2 points. If a number does not have an imaginary or real part you can assume that is equal to 0. As you can notice the number that is not in the shaded area is <span>2 − I</span>

4 0

4 years ago

Please can someone help please

Darya [45]

Answer:

A. 10.2

B.3 √5

3 0

3 years ago