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3 years ago

HELPPP!!!!!

Mathematics

2 answers:

garik1379 [7]3 years ago

7 0

Answer:

Nicole is correct, since when she multiplied by 3, she cleared the x's, since one x was already negative, and the other one was positive. Michael is incorrect since when he multiplied by 2, he didn't realize that both y's were positive, so they didn't clear.

Step-by-step explanation:

Let's see what will happen if we do what Nicole says:

x+2y=7

-3x+4y=9

multiply the first equation by 3 on both sides

3(x+2y)=7(3)

3x+6y=21

-3x+4y=9

now let's add them.

10y=30

We can see that the x's are cleared, since one x is positive and the other is negative.

Now let's try what Michael says.

x+2y=7

-3x+4y=9

multiply first equation by 2

2(x+2y)=7

2x+4y=7

-3x+4y=9

now let's add

-x+8y=16

the y's aren't eliminated, since both of them are positive.

Nicole is correct, since one x is positive and another was negative, and when opposite numbers are added together, they cancel out and equal zero.

Hope this helps!

Kaylis [27]3 years ago

5 0

Answer:

Nicole is correct

Step-by-step explanation:

by multiplying the first equation by 3 it becomes:

3x + 6y =21

this can cancel the -3x in the second equation when adding them together

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a) 3.47% probability that there will be exactly 15 arrivals.

b) 58.31% probability that there are no more than 10 arrivals.

Step-by-step explanation:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

In which

x is the number of sucesses

e = 2.71828 is the Euler number

$\mu$ is the mean in the given time interval.

If the mean number of arrivals is 10

This means that $\mu = 10$

(a) that there will be exactly 15 arrivals?

This is P(X = 15). So

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

$P(X = 15) = \frac{e^{-10}*(10)^{15}}{(15)!} = 0.0347$

3.47% probability that there will be exactly 15 arrivals.

(b) no more than 10 arrivals?

This is $P(X \leq 10)$

$P(X \leq 10) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)$

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

$P(X = 0) = \frac{e^{-10}*(10)^{0}}{(0)!} = 0.000045$

$P(X = 1) = \frac{e^{-10}*(10)^{1}}{(1)!} = 0.00045$

$P(X = 2) = \frac{e^{-10}*(10)^{2}}{(2)!} = 0.0023$

$P(X = 3) = \frac{e^{-10}*(10)^{3}}{(3)!} = 0.0076$

$P(X = 4) = \frac{e^{-10}*(10)^{4}}{(4)!} = 0.0189$

$P(X = 5) = \frac{e^{-10}*(10)^{5}}{(5)!} = 0.0378$

$P(X = 6) = \frac{e^{-10}*(10)^{6}}{(6)!} = 0.0631$

$P(X = 7) = \frac{e^{-10}*(10)^{7}}{(7)!} = 0.0901$

$P(X = 8) = \frac{e^{-10}*(10)^{8}}{(8)!} = 0.1126$

$P(X = 9) = \frac{e^{-10}*(10)^{9}}{(9)!} = 0.1251$

$P(X = 10) = \frac{e^{-10}*(10)^{10}}{(10)!} = 0.1251$

$P(X \leq 10) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10) = 0.000045 + 0.00045 + 0.0023 + 0.0076 + 0.0189 + 0.0378 + 0.0631 + 0.0901 + 0.1126 + 0.1251 + 0.1251 = 0.5831$