Answer:
There are 120 1st graders at Sierra Elementary School this year
Step-by-step explanation:
Let n represent the total number of 1st graders at Sierra Elementary School
Since 45% of all 1st graders at Sierra Elementary School are female students and this year there are 54 female 1st graders, 45% of n is equal to 54
→ n( ) = 54
) = 54
→ 45n = 5400
→ n = 120
 
        
                    
             
        
        
        
Answer:
1716 ways 
Step-by-step explanation:
Given that :
Number of entrants = 13
The number of ways of attaining first, second and third position :
The number of ways of attaining first ; only 1 person can be first ;
Using permutation :
nPr = n! ÷(n-r)!
13P1 = 13! ÷ 12! = 13
Second position :
We have 12 entrants left :
nPr = n! ÷(n-r)!
12P1 = 12! ÷ 11! = 12
Third position :
We have 11 entrants left :
nPr = n! ÷(n-r)!
11P1 = 11! ÷ 10! = 11 
Hence, Number of ways = (13 * 12 * 11) = 1716 ways 
 
        
             
        
        
        
On point (5,1) Fam......................
        
                    
             
        
        
        
Answer:
- table: 14, 16, 18
- equation: P = 2n +12
Step-by-step explanation:
Perimeter values will be ...
rectangles . . . perimeter
   1 . . . 14
   2 . . . 16
   3 . . . 18
__
The perimeter of a figure is twice the sum of the length and width. Here, the length is a constant 6. The width is n, the number of rectangles. So, the perimeter is ...
   P = 2(6 +n) = 12 +2n
Your equation is ...
   P = 2n +12 . . . . . . . . perimeter P of figure with n rectangles.
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<em>Additional comment</em>
You may be expected to write the equation using y and x for the perimeter and the number of rectangles. That would be ...
   y = 2x +12 . . . . . . . . . perimeter y of figure with x rectangles