Answer:
a) Here we have:
"In Family A, the youngest child is 7 years younger than the oldest, who is 18"
Let's define:
Y = age of the youngest child.
O = age of the oldest child.
Then we know that:
Y = O - 7
O = 18
Then we can replace the second equation into the first one:
Y = 18 - 7 = 11.
b) Here we have:
"In Family B, the middle child is 5 years older than the youngest child."
Let's define:
Y = age of the youngest child.
M = age of the middle child.
Here we have only one equation:
M = Y + 5.
 
        
             
        
        
        
Answer:
x=78
Step-by-step explanation:
q is 90 degrees since it is a right angle, 
p=12 
90 plus 12 =102 
x=180-102 
x=78
 
        
                    
             
        
        
        
Answer:

And solving for the radius we got:

And replacing the data given we got:

And this value converted to meters is 
Step-by-step explanation:
For this case we know the population size  and we also know the population density
 and we also know the population density 
We can assume that the area is a circle. We also know that the formula for the population density is given by:

Where P represent the number of people and A the area. Since we are assuming a circle then the area is given by:

With X the radius of the circle 
And then the populationd density become:

And solving for the radius we got:

And replacing the data given we got:

And this value converted to meters is 
 
        
             
        
        
        
I believe it is 1250
Explanation: Area of a triangle=1/2bh-1/2•20•30
Area of square=bh-25•25
Add your answers together then you get 1250