PLEASE HELP ME OUT (geometry)

A:b=3, m:n=2:5. Find a/m:b/m

Strike441 [17]

Answer:

7,5

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

A factory makes 394 motorcycles each week. If there are 52 weeks in a year, how many motorcycles will they make in a year

BigorU [14]

The answer is 7.57 of what they make for each year

5 0

3 years ago

Please find the answer , it is a very importatnt question

Anna [14]

Step-by-step explanation:

The given expression is :

$\dfrac{2-\sqrt5}{2+3\sqrt5}=\sqrt5 x+y$ ....(1)

Taking LHS of the above expression

$\dfrac{2-\sqrt5}{2+3\sqrt5}$

Rationalizing both denominator and numerator.

$\dfrac{2-\sqrt5}{2+3\sqrt5}\times \dfrac{2-3\sqrt5}{2-3\sqrt5}=\dfrac{4-6\sqrt5-2\sqrt5+15}{2^2-(3\sqrt5)^2}\\\\=\dfrac{19-8\sqrt5}{4-45}\\\\=\dfrac{19-8\sqrt5}{-41}\\\\=\dfrac{\sqrt5 \times 8}{41}+(\dfrac{-19}{41})$

Equation (1) becomes,

$\dfrac{\sqrt5 \times 8}{41}+(\dfrac{-19}{41})=\sqrt 5\ x+y$

Equating both sides,

$x=\dfrac{8}{41}$ and $y=\dfrac{-19}{41}$

Hence, this is the required solution.

7 0

3 years ago

Ronald scores 700 on the math section of the SAT exam. The distribution of SAT scores is approximately normal with a mean of 500

Artist 52 [7]

Answer:

a) Due to the higher z-score, Ronald performed better relative to his peers on the test.

b) Ronald needed a grade of at least 732.5, and Rubin of at least 33.58.

c) 95% of the population fall between graded of 4.868 and 31.132 on the ACT.

95% of the population fall between graded of 304 and 696 on the SAT.

Step-by-step explanation:

Normal probability distribution

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:

(a) Relative to their peers who also took the tests, who performed better on his test? Explain.

We have to find whoever has the higher z-score.

Ronald:

Ronald scores 700 on the math section of the SAT exam. The distribution of SAT scores is approximately normal with a mean of 500 and a standard deviation of 100. So the z-score is found when $X = 700, \mu = 500, \sigma = 100$ . So

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

$Z = \frac{700 - 500}{100}$

$Z = 2$

Rubin:

Rubin takes the ACT math exam and scores 31 on the math portion. ACT scores are approximately normally distributed with a mean of 18 and a standard deviation of 6.7. So the z-score is found when $X = 31, \mu = 18, \sigma = 6.7$ . So

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

$Z = \frac{31 - 18}{6.7}$

$Z = 1.94$

Due to the higher z-score, Ronald performed better relative to his peers on the test.

(b) A certain school will only consider those students who score in the top 1% in the math section. What grades would Ronald and Rubin have to receive on their respective tests to be considered for admission?

They have to be in the 100 - 1 = 99th percentile, that is, they need a z-score with a pvalue of at least 0.99. So we need to find for them X when Z = 2.325.

Ronald:

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

$2.325 = \frac{X - 500}{100}$

$X - 500 = 232.5$

$X = 732.5$

Rubin:

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

$2.325 = \frac{X - 18}{6.7}$

$X - 18 = 15.58$

$X = 33.58$

Ronald needed a grade of at least 732.5, and Rubin of at least 33.58.

(c) Between what two grades does 95% of the population fall for the ACT and the SAT exams?

They fall between the 100 - (95/2) = 2.5th percentile and the 100 + (95/2) = 97.5th percentile, that is, they fall between X when Z = -1.96 and X when Z = 1.96.

ACT:

Lower bound:

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

$-1.96 = \frac{X - 18}{6.7}$