All categories

3 years ago

X y

1 answer:

7 0

D) y=3x-7 is the right answer. If you plug in the numbers above you’ll see that those numbers make both sides of the equation equal. Hope I was able to help. Comment if you need further explanation.

You might be interested in

Can you pls help me pls

BartSMP [9]

Answer:A

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

2/3 x -9/8 x -4/5 x -1

jolli1 [7]

-151/120x -1 or 1\120 × (-151x -120)

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

3 years ago

What is the simplified form of the quantity x over 3 plus y over 4 all over the quantity x over 4 minus y over 3? the quantity 4

STatiana [176]

Answer:

Option A) $\frac{4x+3y}{3x-4y}$

Step-by-step explanation:

The given expression is:

$\frac{\frac{x}{3}+\frac{y}{4}}{\frac{x}{4}-\frac{y}{3}}$

Taking LCM in upper and lower fractions, we get:

$\frac{\frac{x}{3}+\frac{y}{4}}{\frac{x}{4}-\frac{y}{3}}\\\\ =\frac{\frac{4x+3y}{12}}{\frac{3x-4y}{12}}\\\\\text{Cancelling out the common factor 12, we get:}\\\\ =\frac{4x+3y}{3x-4y}$

Therefore, the option A gives the correct answer.

6 0

3 years ago

William is 3 years, older than Charmine. The sum of 3 times Charmaine's age and 2 times William's age is 76. How old are William

lana66690 [7]

William is 17 years old and Charmaine is 14 years old.

Step-by-step explanation:

Let x be the age of William and y be the age of Charmaine

Then

William is 3 years, older than Charmine.

x = y+3 Eqn 1

The sum of 3 times Charmaine's age and 2 times William's age is 76.

2x+3y = 76 Eqn 2

Putting x = y+3 in Eqn 2

$2(y+3)+3y=76\\2y+6+3y=76\\5y+6=76\\Subtracting\ 6\ from\ both\ sides\\5y+6-6=76-6\\5y=70\\Dividing\ both\ sides\ by\ 5\\\frac{5y}{5} = \frac{70}{5}\\y=14\\Putting\ the\ value\ of\ y\ in\ Eqn\ 1\\x=y+3\\x=14+3\\x=17$

Hence,

William is 17 years old and Charmaine is 14 years old.

Keywords: Linear equations, Variables

Learn more about linear equations at:

#LearnwithBrainly

5 0

3 years ago