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2 years ago

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1 answer:

4 0

Yesterday, 1/4 of 80 =20 gave their speeches, so there are 80-20=60 students left.
Today, 2/5 of 60=24 students gave their speeches, so there are 60-24=36 students who still haven't give their speeches
another way to think of it is 80*(1- 1/4)*(1- 2/5)=80*(3/4)*(3/5)=36

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Graph f(x) = 4[x] + 5

Elena L [17]

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6 0

2 years ago

A researcher is interested in the lengths of brook trout, which are known to be approximately Normally distributed with mean 80

aliya0001 [1]

Answer:

$P(X$

And we can find this probability with the normal standard distirbution or excel and we got:

$P(z$

Step-by-step explanation:

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

$X \sim N(80,5)$

Where $\mu=80$ and $\sigma=5$

We are interested on this probability

$P(X$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X$

And we can find this probability with the normal standard distirbution or excel and we got:

$P(z$

6 0

2 years ago

Plz help me with number 18

Gala2k [10]

4.15, 6.3, 8.45, 10.6, 12.75
You just subtract 4.15 from 6.3 and you get a difference of 2.15. Then you add it to 8.45 giving you the answer of 10.6 and then you add 2.15 to that getting 12.75.

6 0

3 years ago

Help me pleaseeeeeeeeee

crimeas [40]

Answer:

x=10 and x=-9

Step-by-step explanation:

Factor:

(x-10)(x+9)=0

x-10=0

x=10

and

x+9=0

x=-9

3 0

2 years ago

When we divide 2√3 by 2√3 it gives 3 how ?(2√3/2√3)

S_A_V [24]

Only if the individual doing the calculation makes a substantial mistake.

Any fraction with the same quantity in the numerator and denominator
always has the value of ' 1 ', (provided only that the quantity is not zero).

6 0

2 years ago

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