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3 years ago

Of the following numbers, which one is prime: 14, 13, 21, 33? A. 21 B. 13 C. 14 D. 33

Mathematics

2 answers:

Savatey [412]3 years ago

5 0

The answer is 13 for this question. Good luck!

konstantin123 [22]3 years ago

3 0

The prime number is 13, or B

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A group of 72 children completed a survey on what kind of sport they like. The choices were: Chess, Swimming, and Football. Ever

Svetach [21]

Answer:

19/72

Step-by-step explanation:

To calculate the probability that a randomly-chosen child from this group likes either Chess or Swimming but not Football?

We already know the number that liked chess only which is 10, we have to solve for those that liked swimming only which is

8+7+16+x = 40

x which represent swimming only is

40-31 = 9

Thus probability = 10/72 + 9/72 = 19/72

3 0

3 years ago

Simplify this problem::<br> -6x + 3 3/4 + 14x - 3.25

Lynna [10]

Answer:

8x + 1/2 or 8x + 0.5

Step-by-step explanation:

-6x + 3 3/4 + 14x - 3.25

u can either convert the fraction to a decimal or convert the decimal into a fraction, i'm going to do the latter

-6x + 3 3/4 + 14x - 3 1/4

rearrange to make it easier, don't need to do this i'm just doing this for the sake of it

-6x + 14x + 3 3/4 - 3 1/4

8x + 2/4, simplify this

8x + 1/2

The decimal way if u want:

-6x + 3 3/4 + 14x - 3.25

-6x + 3.75 + 14x - 3.25

-6x + 14x + 3.75 - 3.25

8x + 0.5

6 0

3 years ago

Suppose that a college determines the following distribution for X = number of courses taken by a full-time student this semeste

lidiya [134]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$ In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$ And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

Step-by-step explanation:

Previous concepts

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

Solution to the problem

For this case we have the following distribution given:

X 3 4 5 6

P(X) 0.07 0.4 0.25 0.28

We can calculate the mean with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$

In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$

And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

3 0

3 years ago

I've tried doing the problems and I just don't understand this can someone plz help me

GuDViN [60]

Whats the problem you need help with

5 0

3 years ago

Can u help me please :)

GuDViN [60]

She has to go down 4, back up to 0, and then up another 4, then back to 0.I<span>f positive 1 represents the first level above ground, negative numbers are a good choice to represent levels below ground. 8 flights; starting at -4 and moving to 4.</span>

7 0

3 years ago