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3 years ago

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Anita and Joelle bowled together and their combined total score for one game was 425 points. Anita’s score was 40 less than twic

e Joelle’s. What were their scores? Write a system of equations to model the problem if x represents Joelle’s score and y represents Anita’s score.

1 answer:

wariber [46]3 years ago

6 0

Call Anita's score $"y"$ and Joelle's score $"x"$ .

1) "<span>their combined total score for one game was 425 points"
</span>Therefore $x+y=425$

2)"Anita’s score was 40 less than twice Joelle’s."
Therefore $y=2x-40$

Substitute:
$x+2x-40=425$

Solve:
$3x=465$
$x=155$

Backsubstitute:
$y=2x-40$
$y=2(155)-40$
$y=270$

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I hope this helps.

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Answer:

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Where $\mu=114.8$ and $\sigma=13.1$

We are interested on this probability

$P(X>140)$

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

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

And we can find this probability using the complement rule:

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

$X \sim N(114.8,13.1)$

Where $\mu=114.8$ and $\sigma=13.1$

We are interested on this probability

$P(X>140)$

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: $P(X>140)=P(\frac{X-\mu}{\sigma}>\frac{140-\mu}{\sigma})=P(Z>\frac{140- 1114.8}{2.6})=P(z>1.924)$ And we can find this probability using the complement rule:

$P(z>1.924)=1-P(z$

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3 years ago

which of the following gives an equation of a line that passes through the point (6 over 5, -19 over 5) and is parallel to the l

victus00 [196]

One equation for this would be

$y = \frac{41}{16} x-\frac{55}{8}$

We start by finding the slope between the two points:

$m=\frac{y_2-y_1}{x_2-x_1}=\frac{-12-\frac{-19}{5}}{-2-\frac{6}{5}}
\\
\\=(-12+\frac{19}{5}) \div (-2-\frac{6}{5})
\\
\\=(\frac{-60}{5}+\frac{19}{5}) \div (\frac{-10}{5}-\frac{6}{5})
\\
\\=\frac{-41}{5} \div \frac{-16}{5}=\frac{-41}{5} \times \frac{-5}{16}=\frac{41}{16}$

A line parallel to this one will have the same slope. We will use point-slope form to write our equation:

$y-y_1=m(x-x_1)
\\
\\y-\frac{-19}{5}=\frac{41}{16}(x-\frac{6}{5})
\\
\\y+\frac{19}{5}=\frac{41}{16}x- \frac{41}{16} \times \frac{6}{5}
\\
\\y+\frac{19}{5}=\frac{41}{16}x-\frac{246}{80}
\\
\\y+\frac{304}{80}=\frac{41}{16}x-\frac{246}{80}
\\
\\y=\frac{41}{16}x-\frac{246}{80}-\frac{304}{80}
\\
\\y=\frac{41}{16}x-\frac{550}{80}
\\
\\y=\frac{41}{16}x-\frac{55}{8}$

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3 years ago