Which is the correct classification of<br> 3/8

dangina [55]

N - Nicholes money
M - Marys money

(1) N + M = 4800 ⇒ N = 4800 - M
(2) N - 800 = M - 2/5M ⇒ N - 800 = 3/5M

subtitute (1) to (2)

4800 - M - 800 = 3/5M
4000 - M = 3/5M
-M - 3/5M = -4000
-8/5M = -4000 |multiply both sides by (-5/8)
M = 2500

subtitute the value of M to (1)

N = 4800 - 2500
N = 2300

Answer: Mary had at first $2500. (Nichole: $2300).

5 0

2 years ago

In June 2012, Twitter was reporting 400 million tweets per day. Each tweet can consist of up to 140 characters (letter, numbers,

gulaghasi [49]

Each tweet would cost between 1 and 140 pennies you can write that as an inequality [1 ≤ x ≤ 140] Since you can't tweet 0 characters or above 140.

if you want to change it to pounds divide by 100.

A) 1 ≤ x ≤ 140

B) Each character costs a penny, you can't tweet less than 1 character or above 140.

3 0

2 years ago

A collection of 108 coins containing only quarters and nickels is worth $21. A table titled Coin Collection showing Number of Co

harina [27]

Answer:

q = 108-n

Step-by-step explanation:

Given: 108 coins containing only quarters and nickels

q = 108-n

since total number of coins is 108, and n= number of nickels

If you want to know how many of each kind of coin, read on:

First solve the number of quarters and nickels.

If all 108 coins are quarters, the value is 108*0.25 = $27

Since this value exceed the actual by 27-21 = $6,

we replace a number of quarters by nickels.

Each replacement will reduce the value by 25 - 5 = 20 cents = 0.2 dollars.

So it will take 6/0.2 = 30 replacements.

Therefore there are 108-35 = 78 quarters and 30 nickels.

8 0

2 years ago

Read 2 more answers

Harry and Helen are married, filing jointly. Their combined taxable income is $65,922. Every week, a total of $187 is withheld f

makkiz [27]

Answer:

Your correct answer is d. Harry and Helen will receive a refund of $555. explain please

Step-by-step explanation:

Hope this helps :) -Mark Brainiest Please :)

4 0

2 years ago

Read 2 more answers

An investor believes that investing in domestic and international stocks will give a difference in the mean rate of return. They

arlik [135]

Answer:

So on this case the 90% confidence interval would be given by $-4.137 \leq \mu_1 -\mu_2 \leq 2.087$

For this case since the confidence interval for the difference of means contains the 0 we can conclude that we don't have significant differences at 10% of significance between the two means analyzed.

Step-by-step explanation:

Previous concepts

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 means 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.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X_1 =2.0233$ represent the sample mean 1

$\bar X_2 =3.048$ represent the sample mean 2

n1=15 represent the sample 1 size

n2=15 represent the sample 2 size

$s_1 =4.893387$ population sample deviation for sample 1

$s_2 =5.12399$ population sample deviation for sample 2

$\mu_1 -\mu_2$ parameter of interest at 0.1 of significance so the confidence would be 0.9 or 90%

We want to test:

H0: $\mu_1 = \mu_2$

H1: $\mu_1 \neq \mu_2$

And we can do this using the confidence interval for the difference of means.

Solution to the problem

The confidence interval for the difference of means is given by the following formula:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2}\sqrt{\frac{s^2_1}{n_1}+\frac{s^2_2}{n_2}}$ (1)

The point of estimate for $\mu_1 -\mu_2$ is just given by:

$\bar X_1 -\bar X_2 =2.0233-3.048=-1.0247$

The degrees of freedom are given by:

$df = n_1 +n_2 -2 = 15+15-2=28$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,28)".And we see that $t_{\alpha/2}=\pm 1.701$

Now we have everything in order to replace into formula (1):

$-1.0247-1.701\sqrt{\frac{4.893387^2}{15}+\frac{5.12399^2}{15}}=-4.137$

$-1.0247+1.701\sqrt{\frac{4.893387^2}{15}+\frac{5.12399^2}{15}}=2.087$

So on this case the 90% confidence interval would be given by $-4.137 \leq \mu_1 -\mu_2 \leq 2.087$

For this case since the confidence interval for the difference of means contains the 0 we can conclude that we don't have significant differences at 10% of significance between the two means analyzed.

4 0

2 years ago

Which is the correct classification of 3/8