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Aneli [31]
3 years ago
12

On a standardized exam, the scores are normally distributed with a mean of 79 and a standard deviation of 20. Find the z-score o

f a person who scored 121 on the exam.
Mathematics
1 answer:
Anit [1.1K]3 years ago
3 0

Answer:

z = 2.1

Step-by-step explanation:

z=\frac{x-\mu}{\sigma}\\ \\z=\frac{121-79}{20}\\ \\z=\frac{42}{20}\\ \\z=2.1

This tells us that the person's score of 121 places them 2.1 standard deviations above the mean score of 79.

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Answer:

$0.50 per apple and $2.00 per orange

Step-by-step explanation:

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Help me pls very much appreciated luvs <33
Ludmilka [50]

Answer:

18

Step-by-step explanation:

Since this is a multiple choice question, I will employ the guess and check method - meaning I will check each answer one by one.

Variable x = dimes = $0.10

Variable y = quarters = $0.25

Set up a system of equations:

x + y = 38

x(0.10) + y(0.25) = 6.80

Plug in each choice into the second equation. You can find the number of quarters that correspond to each number of dimes by using the first equation.

20 dimes:

20 + y = 38

y = 18

20(0.10) + 18(0.25) = 6.80

2 + 4.5 = 6.80

6.5 does not equal 6.80

Because dimes (x) are worth less than quarters (y), this result tells us the answer will be less than 20 dimes as with 20 or more we have less than $6.80. Another example just to show this is true:

38 dimes:

38 + y = 38

y = 0

38(0.10) + 0(0.25) = 6.80

3.8 + 0 = 6.80

3.8 does not equal 6.80.

Since x is worth less than y, we need more of y rather than x. Adding more x will only mean we will get a lower price. Adding more y will mean we get a higher price which is what we need. So only solve for x that is less than 20.

6

6 + y = 38

y = 22

6(0.10) + 32(0.25) = 6.80

0.60 + 8 = 8.60

8.60 does not equal 6.80.

This result is higher than what we wanted (6.80) which means we need more x. Now we only have to solve for x numbers that are greater than 6 and less than 20.

18

18 + y = 38

y = 20

18(0.10) + 20(0.25) = 6.80

1.8 + 5 = 6.8

6.8 does equal 6.8.

Correct!

8 0
3 years ago
This contradiction proves that the onginal statement is
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Answer:

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Step-by-step explanation:

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4 0
3 years ago
How many different arrangements of the letters in the word BETTER are there?
Kitty [74]

Answer: There are 180 different arrangements of the letters in the word "BETTER".


Step-by-step explanation:


8 0
3 years ago
Read 2 more answers
Kayla went over the allotted cell phone minutes this month by 42 minutes. Her regular bill is $39.95, but this month is was $54.
Nimfa-mama [501]

\frac{\text{ over time minutes }}{\text{ cost for overtime minute}} = \frac{42}{14.7}

The ratio of overtime minutes to the cost of those minutes is 42 : 14.7

<em><u>Solution:</u></em>

Kayla went over the allotted cell phone minutes this month by 42 minutes

Therefore,

over time minutes = 42 minutes

Her regular bill is $39.95, but this month is was $54.65

Regular bill = $ 39.95

This month bill = $ 54.65

<em><u>Therefore, cost for overtime minute is given by:</u></em>

cost for overtime minute = This month bill - regular bill

cost for overtime minute = $ 54.65 - $ 39.95

cost for overtime minute = 14.7

<em><u>Thus ratio of over time minutes to cost of those minutes is given by:</u></em>

\frac{\text{ over time minutes }}{\text{ cost for overtime minute}} = \frac{42}{14.7}

Thus the required ratio is found

8 0
4 years ago
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