Answer:
If you are talking about the rectangular prism the equation is  
2 × L × W + 2 × L × H + 2 × W × H
If you are talking about Triangular prism the equation is
B × H + L × S + L × B + L × C
 
        
             
        
        
        
For this case we propose a system of equations:
x: Let the variable representing the number of children in the concert
y: Let the variable representing the number of adults at the concert
According to the assistance we have:

According to the cost we have:

Substituting the first in the second equation we have:

Thus, the concert was 375 adults.
On the other hand we have:

Thus, the concert was 1125 children.
In total they were:
 people
 people
ANswer:
The concert was 1500 people
 
        
             
        
        
        
Q1: The perimeter of the triangle is a + b + c and if each side is the same then it's 3a. In this situation we may write it in its simplest form as 9m. Note that 3(3m) is also correct but it's not the simplest form.
Q2: You're correct, the distributive property of 3(3m) can be written as 3 (2m + m).
        
             
        
        
        
The answer is : Sn = S(n-1) + n
        
             
        
        
        
Answer:
Step-by-step explanation:
Josh has a collection of 1,200 music CDs. He considers 1/6 of his collection rock music. This means that the number of rock music CDs that he has is 
1/6 × 1200 = 200
Of the rock music CDs, 20 percent are by solo artist. This means that the number of CDs by solo artist is 
20/100 × 200 = 40
Of the solo artist 2/5 are by female artist. It means that the number done by female solo artists is 
2/5 × 40 = 16