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Crazy boy [7]
3 years ago
5

A math class has 3 girls and 9 boys in the seventh grade and 7 girls and 3 boys in the eighth grade. The teacher randomly select

s a seventh grader and an
eighth grader from the class for competition. What is the probability that the students she selects are both girls?
Write your answer as a fraction in simplest form.
Mathematics
1 answer:
vladimir1956 [14]3 years ago
8 0

Answer:

7/40

Step-by-step explanation:

There are 3 girls+9 boys = 12 students in the 7th grade

P (girl in 7th grade) = girls/ total

                                = 3/12 = 1/4

There are 7 girls+3 boys = 10 students in the 8th grade

P (girl in 8th grade) = girls/ total

                                = 7/10

P(7th grade girl, 8th grade girl) = 1/4 * 7/10 = 7/40

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Which of these can be classified as irrational numbers? explain.
Svetlanka [38]

Answer:

Step-by-step explanation:

ii have no clue what this is

4 0
2 years ago
I really need help guys can some one plz help me it's for 10 points
11111nata11111 [884]

Answer:

\sqrt{8}----- 2units,2units

\sqrt{7} ------\sqrt{5}units,\sqrt{2}units

\sqrt{5}-------1unit,2units

3------2units, \sqrt{5}units

Step-by-step explanation:

Use pythagorean's theorem to solve each pair individually.

The instructions say that you have the two sides (a and b) and you have to match it with their hypothenuse.

Formula: c^2=a^2+b^2

1. a=\sqrt{5}, b=\sqrt{2}

Plug this into the formula.

c=\sqrt{(\sqrt{5} )^2+(\sqrt{2})^2 }

The square here eliminates the roots.

c=\sqrt{5+2}\\ c=\sqrt{7}

2. a=\sqrt{3}, b=4

c=\sqrt{(\sqrt{3} )^2+(4)^2}\\ c=\sqrt{3+16}\\ c=\sqrt{19}

3. a=2, b=\sqrt{5}

c=\sqrt{(2)^2+(\sqrt{5})^2 }\\ c=\sqrt{4+5}\\ c=\sqrt{9}\\ c=3

4. a=2, b=2

c=\sqrt{(2)^2+(2)^2}\\ c=\sqrt{4+4}\\ c=\sqrt{8}

5. a=1, b=2

c=\sqrt{(1)^2+(2)^2}\\ c=\sqrt{1+4}\\ c=\sqrt{5}

7 0
3 years ago
PLEASE HELP THANK YOU!!!
Paul [167]

Answer:

Only C is a function

Step-by-step explanation:

To test whether a graph is a function you use the vertical line test.

If you can place a vertical line anywhere on the plane (in the domain of the "function" to be tested) and it intersects the curve at more than one point, the curve is not a function.

We see with A, wherever we put the vertical line it intersects twice.

With B, it intersects infinitely many times.

C is a function because wherever we put the vertical line, it only intersects once.

D is a function because it intersects twice providing we do not put it on the "tip" of the parabola.

The mathematical reasoning behind this is that a function must be well-defined, that is it must send every x-value to one specific y-value. There can be no confusion about where the function's input is going. If you look at graph B and I ask you what is f(3)? Is it 1? 2? 3? ... Who knows, it's not well-defined and so it's not a function. However if I ask you about C, whichever input value for x I give you, you can tell me to which y-value it gets mapped/sent to.

7 0
3 years ago
what are the minimum first quartile median third quartile and the maximum of the data set? 9,20,4,18,4,18,20,9
den301095 [7]
<u>Answers</u>
1. Minimum = 4
2. First quartile = 6.5
3. Median = 13.5
4. Third quartile = 19
5. Maximum = 20

<u>Explanation</u>
To calculate the measure of central tendency, you first arrange the set of the data in ascending order.  
The set of data given will be;
4, 4, 9, 9, 18, 18, 20, 20.

Part 1:
The minimum value of the data is 4.

Part 2:
The first quatile is the median of the lower half which is comprised by:
4, 4, 9, 9

1st quartile = (4+9)÷2
                  = 13÷2
                  = 6.5

Part 3:
Median of the data is;

Median = (9+18)÷2
              =27÷2
            = 13.5

Part 4:
3rd quartile is the median of the upper half which comprises of; 
18, 18, 20, 20.

3rd quartile = (18+20)÷2
                  = 48÷2
                   = 19

Part 5
The maximum of the set of data is 20.
7 0
3 years ago
Given equation x = 6 + i, w = -1 + 5i and z = 4 - 8i, determine each of the following in the form of a + bi
Temka [501]

Answer:

i) 28 - 30i

ii) 36 + 28i

Step-by-step explanation:

i) x = 6 + i ⇒2x = 2(6 + i) = 12 + 2i

z = 4 - 8i ⇒ 4z = 4(4 - 8i) = 16 - 32i

2x + 4z = (12 + 2i) + (16 - 32i) = 28 - 30i

ii) w = -1 + 5i and z = 4 - 8i

w × z = (-1 + 5i)(4 - 8i) = -4 + 8i + 20i - 40i^{2}⇒collect like terms

w × z = -4 + 28i - 40i^{2}

∵ i^{2}=-1

∴w × z = -4 + 28i - 40(-1) = -4 + 28i + 40 = 36 + 28i

3 0
3 years ago
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