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dalvyx [7]
2 years ago
7

A runner competes in a local marathon. He places 34th which is exactly the top 40% of all runners. How many runners competed

Mathematics
1 answer:
laiz [17]2 years ago
6 0

Answer:

85 runners

Step-by-step explanation:

we know that

34th represent 40% of all runners

so

using proportion

Find out the total number of runners

\frac{34}{40\%}=\frac{x}{100\%}\\\\x=34(100)/40\\\\x= 85\ runners

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To control pollination, pollen-producing flowers are often removed from the top of corn in a process called detasseling. The hou
____ [38]

Answer: <u>Last option</u>

Z_ {13} = 0.5,\ Z_ {17} = 2.5

Step-by-step explanation:

The z-scores give us information about how many standard deviations from the mean the data are. This difference can be negative, if the data are n deviations to the left of the mean, or it can be positive if the data are n deviations to the right of the mean.

To calculate the Z scores, we calculate the difference between the value of the data and the mean and then divide this difference by the standard deviation.

so  

Z = \frac{x- \mu}{\sigma}.

Where x is the value of the data, μ is the mean and σ is the standard deviation

In this case :

μ = 12 $/h

\sigma = 2 $/h

We need to calculate the Z-scores for x = 17 and x = 13

Then for x = 17:

Z_{17} = \frac{17-12}{2}.

Z_{17} = 2.5

Then for x = 13:

Z_{13} = \frac{13-12}{2}.

Z_{13} = 0.5

Therefore the answer is:

Z_ {13} = 0.5,\ Z_ {17} = 2.5

8 0
2 years ago
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Given the trinomial 5x^2-2x-3, predict the type of solutions.
pishuonlain [190]

Consider the trinomial 5x^2-2x-3.

1. Find the discriminant:

D=b^2-4ac=(-2)^2-4\cdot 5\cdot (-3)=4+60=64,\\ \\\sqrt{D}=8>0.

2. Find the roots of given trinomial:

x_{1,2}=\dfrac{-b\pm \sqrt{D}}{2a}=\dfrac{2\pm 8}{2\cdot 5}=1,-0.6.

3. Conclusion: given trinomial has two different real roots.

3 0
2 years ago
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Given: Quadrilateral ABCD is a kite.
Leni [432]

Answer:


Step-by-step explanation:

One

The definition of a kite.

Two

Perpendicular. The diagonals meet at right angles

Three

I don't know if the term is still used, but when I first learned this material (many years ago) we called it the reflexive property.

Four

You found out that <AED = <CED which established that both are right angles. The problem is, you do not have enough information to prove SAS.

AAS is never a dependable reason for proving anything conguent.

HL is really your only choice.

8 0
2 years ago
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A rope is 66 feet long. It is cut into two pieces such that one piece is half the length of the other. What is the length of the
dedylja [7]
So if one bit of the length, is half the size of the other bit then we can make the following equation, for x being the length of rope:

x + 2x = 66
3x = 66
x = 22

That is the length, of the smaller one (half the big one), so 2x = 44. Hence d) is your answer.

Hope I helped!
7 0
2 years ago
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Which is a factor of the polynomial f(x) = 6x4 – 21x3 – 4x2 + 24x – 35?
QveST [7]
<span>I note that this problem starts out with "Which is a factor of ... "  This implies that you were given several answer choices.  If that's the case, it's unfortunate that you haven't shared them.

I thought I'd try finding roots of this function using synthetic division.  See below:

f(x) = 6x^4 – 21x^3 – 4x^2 + 24x – 35
Please use " ^ " to denote exponentiation.  Thanks.

Possible zeros of this poly are factors of 35:  plus or minus 1, plus or minus 5, plus or minus 7.  Use synthetic division; determine whether or not there is a non-zero remainder in each case.  If none of these work, form rational divisors from 35 and 6 and try them:  5/6, 7/6, 1/6, etc.

Provided that you have copied down the function 
</span>f(x) = 6x^4 – 21x^3 – 4x^2 + 24x – 35  properly, this approach will eventually turn up 1 or 2 zeros of this poly.  Obviously it'd be much easier if you'd check out the possible answers given you with this problem.

By graphing this function, I found that the graph crosses the x-axis at 7/2.  There is another root.

Using synth. div. to check whether or not 7/2 is a root:

         ___________________________
7/2   /   6    -21    -4    24    -35
                   21      0   -14     35           
        ----------- ------------------------------
           6        0     -4    10       0

Because the remainder is zero, 7/2 (or 3.5) is a root of the polynomial.  Thus, (x-3.5), or (x-7/2), is a factor.

7 0
2 years ago
Read 2 more answers
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