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2 years ago

9/20+3/18 i need help witth this question

Mathematics

2 answers:

Ugo [173]2 years ago

8 0

Answer:

111/180

Step-by-step explanation:

You find the lcm (loswest common denominator), which is 180. In order to get 180, you times 9 to 20, 10 to 18.

We have to times on the numerator and denominator.

add them together.

111/180

Hope this helps!

Nataliya [291]2 years ago

3 0

Answer:

37/60 OR 111/180

(37/60 is simplified and 111/180 is the original)

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2 years ago

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9 2/5-3 4/10 yo anyone have the answer

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Answer:

Step-by-step explanation:

9 and 2/5 is the equivilent to 9 and 4/10

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2 years ago

Question 3, help please!

White raven [17]

The answer is not defined.

Explanation:

The given matrix is $\left[\begin{array}{cc}{2} & {4} \\ {1} & {-6}\end{array}\right]+\left[\begin{array}{c}{1} \\ {0}\end{array}\right]$

The matrix $\left[\begin{array}{cc}{2} & {4} \\ {1} & {-6}\end{array}\right]$ has dimensions $2\times 2$

This means that the matrix has 2 rows and 2 columns.

Also, the matrix $\left[\begin{array}{l}{1} \\ {0}\end{array}\right]$ has dimensions $2\times1$

This means that the matrix has 2 rows and 1 column.

Since, the matrices can be added only if they have the same dimensions.

In other words, to add the matrices, the two matrices must have the same number of rows and same number of columns.

Since, the dimensions of the two matrices are not equal, the addition of these two matrices is not possible.

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3 years ago

The scores of students on the ACT college entrance exam in a recent year had the normal distribution with mean  =18.6 and stand

Maurinko [17]

Answer:

a) 33% probability that a single student randomly chosen from all those taking the test scores 21 or higher.

b) 0.39% probability that the mean score for 76 students randomly selected from all who took the test nationally is 20.4 or higher

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution:

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.

Central limit theorem:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sample means with size n of at least 30 can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

In this problem, we have that:

$\mu = 18.6, \sigma = 5.9$

a) What is the probability that a single student randomly chosen from all those taking the test scores 21 or higher?

This is 1 subtracted by the pvalue of Z when X = 21. So

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

$Z = \frac{21 - 18.6}{5.4}$

$Z = 0.44$

$Z = 0.44$ has a pvalue of 0.67

1 - 0.67 = 0.33

33% probability that a single student randomly chosen from all those taking the test scores 21 or higher.

b) The average score of the 76 students at Northside High who took the test was x =20.4. What is the probability that the mean score for 76 students randomly selected from all who took the test nationally is 20.4 or higher?

Now we have $n = 76, s = \frac{5.9}{\sqrt{76}} = 0.6768$

This probability is 1 subtracted by the pvalue of Z when X = 20.4. So

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

By the Central Limit Theorem

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

$Z = \frac{20.4 - 18.6}{0.6768}$

$Z = 2.66$

$Z = 2.66$ has a pvalue of 0.9961

1 - 0.9961 = 0.0039

0.39% probability that the mean score for 76 students randomly selected from all who took the test nationally is 20.4 or higher

4 0

2 years ago

Solve x3 = 1 over 8. 1 over 2 ±1 over 2 1 over 4 ±1 over 4

cricket20 [7]

X³ = 1/8

Take the cube root of both sides.

∛x³ = ∛(1/8)

Since x³ has 3 of such x multiplying each other so we bring out 1 of the x from the cube root sign as discussed.

x = ∛((1/2)*(1/2)*(1/2))

We bring out 1 of the (1/2) out of the cube root sign as well.

x = 1/2

So the answer is the first option. 1 over 2.

I hope this helps.

7 0

3 years ago