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lord [1]
3 years ago
7

In a class of 5 , there are 3 students who have done their homework. If the teacher 2 chooses 2 2 students, what is the probabil

ity that none of them have done their homework?
Mathematics
1 answer:
harkovskaia [24]3 years ago
6 0

Answer:

2 over 5

Step-by-step explanation:

This means out of 5 students only three did their work so 5-3=2

And the number of students who did their work over the total number of students in the class to find the probability

You might be interested in
Calculate the sample mean and sample variance for the following frequency distribution of heart rates for a sample of American a
spin [16.1K]

Answer:

Mean = 68.9

s^2 =18.1 --- Variance

Step-by-step explanation:

Given

\begin{array}{cccccc}{Class} & {51-58} & {59-66} & {67-74} & {75-82} & {83-90} \ \\ {Frequency} & {6} & {3} & {11} & {13} & {4} \ \end{array}

Solving (a): Calculate the mean.

The given data is a grouped data. So, first we calculate the class midpoint (x)

For 51 - 58.

x = \frac{1}{2}(51+58) = \frac{1}{2}(109) = 54.5

For 59 - 66

x = \frac{1}{2}(59+66) = \frac{1}{2}(125) = 62.5

For 67 - 74

x = \frac{1}{2}(67+74) = \frac{1}{2}(141) = 70.5

For 75 - 82

x = \frac{1}{2}(75+82) = \frac{1}{2}(157) = 78.5

For 83 - 90

x = \frac{1}{2}(83+90) = \frac{1}{2}(173) = 86.5

So, the table becomes:

\begin{array}{cccccc}{x} & {54.5} & {62.5} & {70.5} & {78.5} & {86.5} \ \\ {Frequency} & {6} & {3} & {11} & {13} & {4} \ \end{array}

The mean is then calculated as:

Mean = \frac{\sum fx}{\sum f}

Mean = \frac{54.5*4+62.5*3+70.5*11+78.5*13+86.5*4}{6+3+11+13+4}

Mean = \frac{2547.5}{37}

Mean = 68.9 -- approximated

Solving (b): The sample variance:

This is calculated as:

s^2 =\frac{\sum (x - \overline x)^2}{\sum f - 1}

So, we have:

s^2 =\frac{(54.5-68.9)^2+(62.5-68.9)^2+(70.5-68.9)^2+(78.5-68.9)^2+(86.5-68.9)^2}{37 - 1}

s^2 =\frac{652.8}{36}

s^2 =18.1 -- approximated

5 0
3 years ago
Wilhema bought 6 bars of soap for $12. The next day, Sophia bought 10 bars of the same kind of soap for $20. What is the cost of
kaheart [24]

Answer:

$2

Step-by-step explanation:

To get this number you can divide the cost by the amount of bars of soap.

12/6=2

20/10=2

Hope this helps!


8 0
3 years ago
-2x-7≥41 in algaebra for
dexar [7]

Answer:

They are equal. x= -24

Step-by-step explanation:

-2x - 7 ≥ 41

First you isolate the variable

-2x -7 ≥ 41

    +7     +7

-2x≥48

then divide each side by -2

x≥-24

Then go back and plug in

-2(-24)-7=

48-7=41

Therefore

41=41

4 0
3 years ago
Pleaseee help me out !!!
Dahasolnce [82]

Answer:

y = 16

Step-by-step explanation:

y = 11 - x

of x is -5, subtitute it into the equation

y = 11 - (-5)

y = 11 + 5

y = 16

8 0
2 years ago
Read 2 more answers
What is the answer? -9=3+6x
HACTEHA [7]
Use inverse operations and subtract 3 from 9 which is -12 then divide -12 by 6 which is -2
-9=3+6x
-3 -3
-12=6x
-12/6=6x/6
-2=x
6 0
3 years ago
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