It would be B because you would take amelias age and take two away since todd is five years younger to get the a-5.
hope this helps :)
Usually you are given more information about the rectangle such as distance of length in terms of width.
You know that the formula for perimeter is
P=2(l+w)
Substitute p and the other values to find width.
Hope I helped :)
Answer:
Part A) see the explanation
Part B) 
Step-by-step explanation:
Part A)
we know that
A relationship between two variables, x, and C, represent a proportional variation if it can be expressed in the form
or 
Let
C ---> is the total cost (represent the output or dependent variable)
x ----> is the number of books (represent the input or independent variable)
In this problem
we have a proportional relationship between the variables x and C
Part B) we know that
The linear equation is given by

The constant of proportionality k is the same that the slope or unit rate of the linear equation
In this problem the constant k is given

so

For x=12 books
substitute in the equation and solve for C

In function notation

It form a right triangle
legnth of ladder is hypotonuse
bottom of ladder from wall distance is one leg
distance up wall is other leg
a^2+b^2=c^2
c=hypotonuse and a and b are legs
4^2+b^2=20^2
16+b^2=400
minus 16 both sides
b^2=384
sqrt both sides
b=8√6 ft
aprox
b=19.59ft from ground