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3 years ago

Serena bought 4 packs of pencils and 12 notebooks

Mathematics

2 answers:

Olin [163]3 years ago

6 0

Answer:

Step-by-step explanation:

that is what it said the correct answer was

Anarel [89]3 years ago

5 0

Answer: pencil (x) = 3.00, notebook (y) = 4.00

Step-by-step explanation:

Let pencils be denoted using 'x', and notebooks 'y'.

4x+12y = 60, 14x+7y=70

Let us use the method of elimination. However, neither variable has the same coefficient, so let us multiply the first equation using 7, and the second using 2.

7(4x+12y = 60) => 28x+84y=420

2(14x+7y=70) => 28x+14y=140

Let us subtract the second equation from the first. This eliminates the first variable x, and gives the equation 70y=280

Dividing either side of the equation by 70, we get y=4.

If we substitute (plug in) y=4 for the first equation we get x=3

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Suppose that the weights of passengers on a flight to Greenland on Frigid Aire Lines are normal with mean 175 pounds and standar

Natali5045456 [20]

Answer:

The minimum weight for a passenger who outweighs at least 90% of the other passengers is 203.16 pounds

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 175, \sigma = 22$

What is the minimum weight for a passenger who outweighs at least 90% of the other passengers?

90th percentile

The 90th percentile is X when Z has a pvalue of 0.9. So it is X when Z = 1.28. So

$Z = \frac{X - \mu}{\sigma}$

$1.28 = \frac{X - 175}{22}$

$X - 175 = 22*1.28$

$X = 203.16$

The minimum weight for a passenger who outweighs at least 90% of the other passengers is 203.16 pounds

6 0

3 years ago

A book store has twice as many history books as science books. The store has 81 history and science books altogether how many of

atroni [7]

let h= history books

science books = s

h=2s there are 2 times as many history as science so to get them equal we double the science

h+s=81 there are 81 total history and science books

2s+s=81 substitute 2s for h in the above equation

3s = 81 combine like terms

s = 27

There are 27 science books

h=2s

h=2(27)

h=54

there are 54 history books

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3 years ago

Pls help for a crown thing

BigorU [14]

Answer:

the answer is c

Step-by-step explanation:

just is.

8 0

3 years ago

Old me yall I look way WAY betta now I got dreads braces I’m taller and I got blue eyes so ye

Anestetic [448]

Answer:

STOP

Step-by-step explanation:

People actually want to answer questions.

6 0

2 years ago

Read 2 more answers

In central city, a property owner pays school taxes at the rate of 2% of the first $1500 of assessed valuation, 3% of the next $

iVinArrow [24]

The first $1500 is taxes at 2%, which comes out to $30.
The next $3000 is taked at 3%, which comes out to $90.
This leaves a remainder of $8000-($1500+$3000). That'd be $3500.
Williams must pay 6% of that $3500, or $210.

His total tax bill would then be $210+$90+$30, or $330.

7 0

3 years ago