Need help solving these 3 equations, please help.

HELPPP MY HW IS DUE IN 5 MINUTES. WHATS 2 PLUS 2. PLZZZ ANSWER QUICKKKK

svp [43]

Answer: 4

Step-by-step explanation: 2+2 is 4

8 0

2 years ago

Read 2 more answers

A shopkeeper fixed the marked price of his radio to make a profit of 30 percentage. allowing rs 30 as a discount then the profit

dusya [7]

Answer:

rs 200

Step-by-step explanation:

Let cost price = x

At 30% profit; marked price of radio is 30% of x = (100% + 30%) = 130%x

Discount = rs 3%

Profit made = 30

Hence,

Marked price - discount = cost price + 30

130%x - 30 = x + 30

1.3x - 30 = x + 30

1.3x - x = 30 + 30

0.3x = 60

Divide both sides by 0.3

0.3x / 0.3 = 60/ 0.3

x =

1.3x / 1.3 = 60 / 1.3

x = 200

Hence, cost price = rs 200

7 0

3 years ago

Estimate the minimum and maximum ages for typical textbooks currently used in college courses, then use the range rule of thumb

Maksim231197 [3]

Answer:

$n=(\frac{1.64(4)}{0.25})^2 =688.537 \approx 689$

So the answer for this case would be n=689 rounded up to the nearest integer

Step-by-step explanation:

Assuming this complete question: "Suppose that the minimum and maximum ages for typical textbooks currently used in college courses are 0 and 8 years. Use the range rule of thumb to estimate the standard deviation.

Estimate the minimum and maximum ages for typical textbooks currently used in college courses, then use the range rule of thumb to estimate the standard deviation. Next, find the size of the sample required to estimate the mean age (in years) of textbooks currently used in college courses. Use a 90% confidence level and assume that the sample mean will be in error by no more than 0.25 year."

Solution for the problem

First we need ti find the estimation for the standard deviation using the Rule of thumb, with the following formula:

$s \approx \frac{R}{4}$

Where R is the range defined as :

$R = Max - Min = 8-0 = 8$

So then the deviation would be approximately:

$s \approx 4$

Important 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 (ME) 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".

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

And on this case we have that $ME =\pm 0.25$ and we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (2)

We can assume that the estimator for the population deviation from the rule of thumb is $\hat \sigma = s= 4$

The critical value for 90% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.05;0;1)", and we got $z_{\alpha/2}=1.64$ , replacing into formula (2) we got:

$n=(\frac{1.64(4)}{0.25})^2 =688.537 \approx 689$

So the answer for this case would be n=689 rounded up to the nearest integer

6 0

3 years ago

What is 4/10 times 8/10???

pshichka [43]

Answer:

8/25

Step-by-step explanation:

We do this by multiplying the top first, and we get 32.

We then multiply the bottom, and get 100.

You might think the answer is 32/100.

Well, kind of! We need to simplify!

we divide the top and bottom by four to get our answer, 8/25.

3 0

3 years ago

Find the area of the triangle below. Be sure to include the correct unit in your answer.

Andru [333]

Answer:

Step-by-step explanation:

3 0

3 years ago