Ask question

Ask question

All categories

2 years ago

7

20% of all the children in a class are left handed. 4 children are left handed. How many children are there in the class all tog

ether?

1 answer:

Katarina [22]2 years ago

7 0

There are 20 students all together.

You might be interested in

Can someone help me in question 28 please

AnnyKZ [126]

Answer: You would get 1 for the first section

Step-by-step explanation: you square whatever number is the x then you cube the x.

6 0

2 years ago

Which equation represents the sentence?

Sunny_sXe [5.5K]

<span>4x + 7 = 32
...................</span>

7 0

3 years ago

Persons taking a 30-hour review course to prepare for a standardized exam average a score of 620 on that exam. Persons taking a

Alina [70]

Given:

30-hour review course average a score of 620 on that exam.

70-hour review course average a score of 749.

To find:

The linear equation which fits this data, and use this equation to predict an average score for persons taking a 57-hour review course.

Solution:

Let x be the number of hours of review course and y be the average score on that exam.

30-hour review course average a score of 620 on that exam. So, the linear function passes through the point (30,620).

70-hour review course average a score of 749. So, the linear function passes through the point (70,749).

The linear function passes through the points (30,620) and (70,749). So, the linear equation is:

$y-y_1=\dfrac{y_2-y_1}{x_2-x_1}(x-x_1)$

$y-620=\dfrac{749-620}{70-30}(x-30)$

$y-620=\dfrac{129}{40}(x-30)$

$y-620=\dfrac{129}{40}(x)-\dfrac{129}{40}(30)$

$y-620=\dfrac{129}{40}(x)-\dfrac{387}{4}$

Adding 620 on both sides, we get

$y=\dfrac{129}{40}x-\dfrac{387}{4}+620$

$y=\dfrac{129}{40}x+\dfrac{2480-387}{4}$

$y=\dfrac{129}{40}x+\dfrac{2093}{4}$

We need to find the y-value for $x=57$ .

$y=\dfrac{129}{40}(57)+\dfrac{2093}{4}$

$y=183.825+523.25$

$y=707.075$

$y\approx 707.1$

Therefore, the required linear equation for the given situation is $y=\dfrac{129}{40}x+\dfrac{2093}{4}$ and the average score for persons taking a 57-hour review course is 707.1.

4 0

2 years ago

What is (12-2i) (5+3i) multiplied?

Ilya [14]

= 12*5 + 12*3i - 5*2i - 6i^2 (remember that i^2 = -1) so:-

= 60 +26i - 6*(-1)

= 60 + 26i + 6

= 66 + 26i

5 0

3 years ago

Given that z is a standard normal random variable, find z for each situation. The area between 0 and z is .4750. Answer The area

algol13

Answer:

$P(0$

And solving for z we have

$P(Z$

And we can find the value for z with the following excel code:

"=NORM.INV(0.975,0,1)"

And we got z =1.96

$P(Z>z)= 0.1314$

And we can use the complement rule and we got:

$P(Z>z) = 1-P(Z$

$P(Z$

And we can find the value for z with the following excel code:

"=NORM.INV(0.8686,0,1)"

And we got z =1.120

$P(Z$

And we can find the value for z with the following excel code:

"=NORM.INV(0.67,0,1)"

And we got z =0.440

Step-by-step explanation:

Previous concepts

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 Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

We want this probability:

$P(0$

And solving for z we have

$P(Z$

And we can find the value for z with the following excel code:

"=NORM.INV(0.975,0,1)"

And we got z =1.96

For the next part we want to calculate:

$P(Z>z)= 0.1314$

And we can use the complement rule and we got:

$P(Z>z) = 1-P(Z$

$P(Z$

And we can find the value for z with the following excel code:

"=NORM.INV(0.8686,0,1)"

And we got z =1.120

For the next part we want to calculate:

$P(Z$

And we can find the value for z with the following excel code:

"=NORM.INV(0.67,0,1)"

And we got z =0.440

6 0

3 years ago