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Veseljchak [2.6K]
3 years ago
12

In a class of 23 student the girls were 7 more than the boys how many boys were in the class​

Mathematics
1 answer:
Softa [21]3 years ago
5 0

Answer:

x=# of boys

x+7=# of girls

x+x+7=25

2x+7=25

2x=25-7

2x=18

x=18/2

x=9 boys

x+7=16 girls

 

If you don't understand variables use trial and error.

 

Boys     Girls

1           8

2           9

3           10

4           11

5           12

6           13

7           14

8           15

9           16   9+16=25 students

 

You could start this way...

 

Boys     Girls

12        13

11        14

10        15

9          16     16 is 7 more than 9

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The sum of two numbers is 12. The difference of the same two numbers is 24. what is the larger of the two numbers
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ANSWER


The larger number is 18

<u>EXPLANATION</u>

Let x be the larger number and y be the smaller  number.


Then,

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Let us add equation (1) and (2).


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Put x=18 in to equation (1).

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Answer:

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Answer:

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\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}} (1)  

Since the Confidence is 0.95 or 95%, the value of \alpha=0.05 and \alpha/2 =0.025, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that z_{\alpha/2}=1.96  

Now we have everything in order to replace into formula (1):  

29.4-1.96\frac{7}{\sqrt{10}}=25.06  

29.4+1.96\frac{7}{\sqrt{10}}=33.74  

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Part b

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We can replace in formula (1) the info given like this:  

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Give the appropriate conclusion for the test

Since is a one side right tailed test the p value would be:  

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Answer:

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3 0
2 years ago
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