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2 years ago

2) Last Friday, Trevon had $17.64.

Mathematics

1 answer:

gregori [183]2 years ago

6 0

Answer:

$14.54

Step-by-step explanation:

We use the equation 32.18-17.64 to find our answer of $14.54

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What is the least common denominator of the fraction 2 over x plus the fraction x over x plus 1 plus the fraction x plus 1 over

Anna71 [15]

3x is the least common denominators because you need to be able to make sure all other denominators can go multiple into it. Since the rest are just x, the largest number of 3x would be the denominator you want.

5 0

3 years ago

Two triangular roofs are similar. The ratio of the corresponding sides of these roofs is 2:3. If the altitude of the smaller roo

schepotkina [342]

Answer: 6.75 feet

Step-by-step explanation:

Since, the ratio of the side of the similar triangle = 2 : 3

Thus, by the property of similar triangle,

The ratio of the altitudes of the triangle = 2 : 3

Let the altitude of smaller triangle = 2 x

And, the altitude of larger triangle = 3 x

Where x is any number.

According to the question,

2 x = 4.5

x = 2.25

Therefore, the altitude of larger triangle = 3 × 2.25 = 6.75 feet

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3 years ago

A random sample of 20 students yielded a mean of ¯x = 72 and a variance of s2 = 16 for scores on a college placement test in mat

Helen [10]

Answer:

The 98% confidence interval for the variance in the pounds of impurities would be $8.400 \leq \sigma^2 \leq 39.827$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =16$ represent the sample variance

s=4 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

Confidence=98% or 0.98

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=20-1=19$

Since the Confidence is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and we can use excel, a calculator or a table to find the critical values.