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Anastaziya [24]
3 years ago
6

A group of students at a school takes a history test. The distribution is normal with a mean of 25, and a standard deviation of

4. (a)Everyone who scores in the top 30% of the distribution gets a certificate. What is the lowest score someone can get and still earn a certificate?
Mathematics
1 answer:
Anna [14]3 years ago
8 0

Answer:

27.1

Step-by-step explanation:

Given:

mean=25

standard deviation=4

z0.70=0.525

z=\frac{x-mean}{standard deviation}

z*sd = x-mean= 2.1

the  lowest score for the top 30%: x=27.1

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Jose is 8 years older than his sister. The sum of their ages is 20. How old is Jose?<br> yrs. old
Mashutka [201]

Answer:

He is 20 years old.

Step-by-step explanation:

cuz 20 - 8 = 12(sisters age)

so if the sum of both their ages is 20 then, he is 20.

3 0
3 years ago
What are all of the real roots of the following polynomial? f(x) = x5 + 5x4 - 5x3 - 25x2 + 4x + 20
Nadusha1986 [10]
F(x)=x^5 + 5*x^4 - 5*x^3 - 25*x^2 + 4*x + 20

By examining the coefficients of the polynomial, we find that
1+5-5-25+4+20=0 => (x-1) is a factor
Now, reverse the sign of coefficients of odd powers,
-1+5+5-25-4+20=0 => (x+1) is a factor

By the rational roots theorem, we can continue to try x=2, or factor x-2=0
2^5+5(2^4)-5(2^3)-25(2^2)+4(2)+20=0
and similarly f(-2)=0
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The remainder can be found by synthetic division as x=-5


Answer: The real roots of the given polynomial are: {-5,-2,-1.1.2}

8 0
3 years ago
Read 2 more answers
How many pumpkins do I have ? If I give half of my pumpkins to my friend Tom and then give half of what is left to my friend Zar
Novosadov [1.4K]
What this is essentially asking is six is half of a number which is half of a number, or six times two times two.

6*2*2 \\  \\ 12*2 \\  \\ 24

You have 24 pumpkins.
5 0
3 years ago
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A rectangle is reduced by the scale factor of 1/4 which of these choices show the ratio of the area of the smaller to the area o
ExtremeBDS [4]

Answer:

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Step-by-step explanation:

I used a rectangle with the side length of 1 to model this for me. You can choose any number, but 1 is easy to multiply.

If the original rectangle had a side length of 1 and 1, the area would be 1.

If you reduce the size to 1/4th of the size, the area would be 0.0625, or 1/16th of the original.

I hope this helped!

6 0
3 years ago
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9 times as much as 7 tenths
Nata [24]

6.3

Take 9 times .7

9 x .7= 6.3

5 0
3 years ago
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