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2 years ago

Help now pls !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mathematics

2 answers:

Natasha_Volkova [10]2 years ago

8 0

Answer:

D. 25

Step-by-step explanation:

You can solve this by saying that he gained 2 points 13 times, and lost half a point two times.

2 * 13 - 0.5 * 2

= 26 - 1

= 25

So his final score was 25.

meriva2 years ago

5 0

D. 25

This is the answer

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There are 33 of them altogether and pay £311 in total. How many kids are in the family? Adults pay £15 and kids pay £7

Marrrta [24]

Answer:

Step-by-step explanation

Let x be the number of adults and y the number of kids

We can then write this two equations :

x+y= 33

15x+7y= 311

let's solve the two eaquations

to do that we should combine them both in a way that help us get rid of one of the variables.

Let's multiply the first equation by -7 to get rid of y by adding it to thr second equation

-7x-7y= -231

now add both equations .

15x+7y-7x-7y=311-231

we get : 8x = 80

as you notice y is gone and we get a classic easy equation to solve

x= 80/8

= 10

so the number of adults is 10

let's go back to the first equation ( x+y= 33) and replace x with 10

10+y= 33

y= 33-10

=23

let's check using the second equation :

(10*15)+(23*7) = 311

that is true

so :

the number of adults is 10
the number of kids is 23

4 0

3 years ago

Why is the mechanical advantage of using a single pulley always 1? Assume there’s no friction. A. The input force is in a differ

Luba_88 [7]

Answer:

D. The input force is equal to the output force

Step-by-step explanation:

A pulley changes the direction of the applied force, but does not change its magnitude. The mechanical advantage is the ratio of output force to input force, so must be 1 when the force magnitude does not change.

8 0

3 years ago

Factor completely:<br> 21) x2 – 2x - 8

mojhsa [17]

Answer: x = -2 and 4

Step-by-step explanation:

x^2 - 2x - 8 = 0

(x - 4)(x + 2) = 0

4 0

3 years ago

Find the Value of 8 1/3

Inessa [10]

$8^{ \frac{1}{3} } = \sqrt[3]{8} = 2$

$8^{ \frac{2}{3} } = \sqrt[3]{8^2} = \sqrt[3]{64} = 4$

8 0

3 years ago

In a list of households, own homes and do not own homes. Five households are randomly selected from these households. Find the p

hichkok12 [17]

Answer:

The probability of success for this case would be:

$p =\frac{9}{15}= 0.6$ representing the proportion of homes that are own homes

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=15, p=0.6)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

And we want this probability:

$P(X=3)$

And uing the probability mass function we got:

$P(X=3)= 15C3 (0.6)^3 (1-0.6)^{15-3}= 0.00165$

Step-by-step explanation:

Adduming the following info: In a list of 15 households, 9 own homes and 6 do not own homes. Five households are randomly selected from these 15 households. Find the probability that the number of households in these 5 own homes is exactly 3.

Round your answer to four decimal places

P (exactly 3)=

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

The probability of success for this case would be:

$p =\frac{9}{15}= 0.6$ representing the proportion of homes that are own homes

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=15, p=0.6)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

And we want this probability:

$P(X=3)$

And uing the probability mass function we got:

$P(X=3)= 15C3 (0.6)^3 (1-0.6)^{15-3}= 0.00165$

4 0

2 years ago