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3 years ago

Gareth 30 students in a class and the ratio of boys to girls in the class is 2:3 calculate the number of goals

Mathematics

1 answer:

pishuonlain [190]3 years ago

8 0

Answer:

<em>There are 12 boys and 18 girls</em>

Step-by-step explanation:

<u>Equations</u>

There are 30 students in a class. Let's call:

x = number of boys

Since the sum of boys and girls is 30:

30 - x = number of girls

The ratio of boys to girls is 2:3, thus:

$\displaystyle \frac{x}{30-x}=\frac{2}{3}$

Crossing denominators:

3x = 2(30 - x)

Operating the parentheses:

3x = 60 - 2x

Adding 2x:

5x = 60

Dividing by 5:

x = 60/5 = 12

x = 12

There are 12 boys and 30-12=18 girls

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Please answer all parts as I know the answers but need the work to go with them. Thus, I believe the above answers are correct.

vampirchik [111]

As the sample size n is less than 30 normal distribution is used.

The values of x are converted into z by using the formula z= x-u/ s and then the z values are found out from the table.

The limits are found by using the formula x±σz or x±sz where s= σ

As the sample size is 10 which is less than 30 the normal distribution is used.

The probability of x< 2.59 is 0.3446

The probability 2.60<X <2.63 is 0.9484

So lower and upper limits are 2.607 and 2.612

Part A

As the sample size is 10 which is less than 30 the normal distribution is used.

Part B

For given value of x= 2.59 z is obtained =0.4

x= 2.59

z= x-u/ s

z= 2.59-2.61/0.05

z= -0.02/0.05

z=- 0.4

P (X<2.59) = P(-0.4 <Z<0) = 0.5 -0.1554= 0.3446

The probability of x< 2.59 is 0.3446

Part C

For two given values of x= 2.60 and 2.63 z is obtained as =0.2 and 0.4

x1= 2.60

z1= x-u/ s

z= 2.60-2.61/0.05

z= -0.01/0.05

z=- 0.2

x2= 2.63

z2= x-u/ s

z= 2.63-2.61/0.05

z= 0.02/0.05

z= 0.4

P (2.60<X<2.63) = P(-0.2 <Z<0.4)

= P(-0.2 <Z<0)+ P(0 <Z<0.4)

=0.793 + 0.1554= 0.9484

The probability 2.60<X <2.63 is 0.9484

Part D"

p= 0.57

From the table z= 0.045

z= x-u/ s

zs= x-u

zs+u = x

x1= 0.045*0.05 +2.61= 2.61225

x2= 2.61- 0.00225= 2.60775

So lower and upper limits are 2.607 and 2.612

For further understanding of probability calculation click

brainly.com/question/25638875

#SPJ1

8 0

2 years ago

Can someone help simplify?: -8x^3y2(2x^4y^4)

Kisachek [45]

So the rule with multiplying exponents of the same base is to add the exponents together. Applying this rule here would look like this:

$-8x^3y^2*2x^4y^4=(-8*2)x^{3+4}y^{2+4}=-16x^7y^6$

In short, your simplified expression is going to be -16x^7y^6.

3 0

3 years ago

^^^!!! 25 pOinTs (seriously help)

bonufazy [111]

Answer:

A) Θ = 2A/r²

Step-by-step explanation:

A = Θr²/2

(Multiple both sides by 2)

2A = Θr²

(Divide both sides by r²)

2A/r² = Θ

7 0

3 years ago

Answer PLS

Zolol [24]

Answer:

yes, your score is good for a seventh grader.

keep it up and you can score more.

8 0

2 years ago

Read 2 more answers

A right triangle has sides of lengths 18 , 24 , and 30 units. What is the area of the triangle? Draw the shape on a grid to h

Elden [556K]

Answer:216

Step-by-step explanation:The formula to find the area of a triangle is Length times Base divided by 2. The length of the triangle could be 18 or 24, but that doesn’t matter. The base could also be 18 or 24, but that also doesn’t matter, because the hypotenuse (the longest part of a right triangle, in this case being 30), is not a part of the formula. 18 times 24 is 432, and 432 divided by 2 is 216. So the area is 216

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3 years ago