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3 years ago

Solve these two equations

Mathematics

1 answer:

tangare [24]3 years ago

8 0

Answer:

a.(2/7,31/7) b.(97,71)

Step-by-step explanation:

im not writing all the work i did its just substitution of the value of x and y from the second equation to the first

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A psychology professor assigns letter grades on a test according to the following scheme. A: Top 10% scores, B: Scores below 10%

stich3 [128]

Answer:

The numerical limits for a D grade is between 57 and 64.

Step-by-step explanation:

When the distribution is normal, we use 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 question:

$\mu = 71.5, \sigma = 9.5$

D: Scores below the top 80% and above the bottom 7%

Between the 7th and the 100 - 80 = 20th percentile.

7th percentile:

X when Z has a pvalue of 0.07. So X when Z = -1.475.

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

$-1.475 = \frac{X - 71.5}{9.5}$

$X - 71.5 = -1.475*9.5$

$X = 57.49$

So 57

20th percentile:

X when Z has a pvalue of 0.2. So X when Z = -0.84.

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

$-0.84 = \frac{X - 71.5}{9.5}$

$X - 71.5 = -0.84*9.5$

$X = 63.52$

So 64

The numerical limits for a D grade is between 57 and 64.

7 0

2 years ago

Kris forwards an e-mail to 5 people. each of those people forward that e-mail to 5 more people. if this happens two more times,

Mila [183]

The answer is D. It can't be A, because that would be if 4 people forwarded it to 5 people each. It can't be B, because that would be Kris, the people she forwarded it to, and the people they forwarded it to, it can't be C, because that the people Kris forwarded it to, the people they forwarded it to, and the people they forwarded it to, it's missing the 4th round of people. So it must be D.

8 0

2 years ago

Over a two-day period, 5/12 of a foot of snow fell in western New York. If 1/3 of a foot of snow fell on the first day, how much

Karolina [17]

B because 1/3 is 4/12 and 5/12 take away 4/12 is 1/12

8 0

2 years ago

Read 2 more answers

. Multiply (5x2 + x − 4)(x + 2).

zubka84 [21]

Answer: 5x2+3x -dx x3 2x2

Step-by-step explanation: