If y varies inversely with x, and y is 8 when x is 5, find y when x is 2.

ladessa [460]

7. You are finding the area of the box. Not the cube, just a surface. Length times width of the surface. Eliminate other numbers and multiply

24.5×19.5

then

26×24.5

8. You are doing the same thing almost. Word problems are scary, but look for the numbers.

4inch ×8inch × 12inch

Find the volume
Multiply the volume by 3, that'd one answer
Devide the ORIGINAL volume by 2. don't divide the volume you multiplied by 3.

8 0

2 years ago

In triangles DEF and OPQ, ∠D ≅ ∠O, ∠F ≅ ∠Q, and segment DF ≅ segment OQ. Is this information sufficient to prove triangles DEF a

zalisa [80]

Answer:

We can't prove this with the SAS postulate.

Step-by-step explanation:

SAS means that two sides and the angle between those two sides are equal.

Side Angle Side (SAS)

That's why we can't prove this with the SAS postulate.

3 0

1 year ago

A proper fraction is converted to a decimal equivalent by dividing the denominator into the numerator. True

kondaur [170]

False, it's the other way around: you divide the numerator by the denominator.

For example, to evaluate $\frac{8}{15}$ you divide 8 by 15:

$\dfrac{8}{15} = 8\div 15 = 0.5\overline{3}$

7 0

3 years ago

There are 48 students in an elementary statistics class. On the basis of years of experience, the instructor knows that the time

Stella [2.4K]

Answer:

a) 64.06% probability that he is through grading before the 11:00 P.M. TV news begins.

b) The hardness distribution is not given. But you would have to find s when n = 39, then the probability would be 1 subtracted by the pvalue of Z when X = 51.

Step-by-step explanation:

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

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.

Central Limit Theorem

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

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For the sum of n trials, the mean is $\mu*n$ and the standard deviation is $s = \sigma\sqrt{n}$

In this question:

$n = 48, \mu = 48*5 = 240, s = 4\sqrt{48} = 27.71$

These values are in minutes.

(a) If grading times are independent and the instructor begins grading at 6:50 P.M. and grades continuously, what is the (approximate) probability that he is through grading before the 11:00 P.M. TV news begins?

From 6:50 PM to 11 PM there are 4 hours and 10 minutes, so 4*60 + 10 = 250 minutes. This probability is the pvalue of Z when X = 250. So

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

By the Central Limit Theorem

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

$Z = \frac{250 - 240}{27.71}$

$Z = 0.36$

$Z = 0.36$ has a pvalue of 0.6406

64.06% probability that he is through grading before the 11:00 P.M. TV news begins.

(b) What is the (approximate) probability that the sample mean hardness for a random sample of 39 pins is at least 51?

The hardness distribution is not given. But you would have to find s when n = 39(using the standard deviation of the population divided by the square root of 39, since it is not a sum here), then the probability would be 1 subtracted by the pvalue of Z when X = 51.

5 0

2 years ago

Giving brainliestttt

Nataly [62]

Answer:

Jupiter is so big that all the other planets in the solar system could fit inside it. More than 1,300 Earths would fit inside Jupiter. Jupiter is the fifth planet from the sun. From Earth, it is almost always the second brightest planet in the night sky.

7 0

2 years ago