It is 18 because the radius is half the diameter and 9 x 2 = 18.
No solution is the answer love
Answer:
Cost of one roll of plain wrapping: 
Cost of one roll of holiday wrapping paper: 
Step-by-step explanation:
Let be "p" the cost in dollars of one roll of plain wrapping paper and "h" the cost in dollars of one roll of holiday wrapping paper.
Based on the information given, we can set up this system of equations:

In order to solve it, we can use the Substitution method. The steps are:
1. Solve for "p" from the first equation:

2. Substitute the above into the second equation and solve for "h":
3. Substitute the value of "h" into
:

Let
x----------> the first number
y---------> the second number
z--------> the third number
we know that
x+y+z=19-----> z=19-x-y------> equation 1
2x+4y+5z=72-----> equation 2
4x-y=12------> equation 3
substitute equation 1 in 2
2x+4y+5*[19-x-y]=72----> 2x+4y+95-5x-5y=72----> -3x-y=-23
3x+y=23------> equation 4
add equation 3 and equation 4
4x-y=12
3x+y=23
--------------
7x+0y=35--------> x=35/7----------> x=5
4x-y=12------> y=4x-12----> y=4*5-12----> y=8
z=19-x-y------> z=19-5-8----> z=6
the answer is
the numbers are
5
8
6