Mary is incorrect. Perimeter is not proportional to area. An example which you can use is garden A is an 8 by 1 rectangle. The perimeter is 18 while the area is 8. Graden B is a 4 by 4 square. The perimeter is 16 (less than garden A) while the area is 16 (two times more than garden B).
Anything multiplied by zero is zero
Let us formulate the independent equation that represents the problem. We let x be the cost for adult tickets and y be the cost for children tickets. All of the sales should equal to $20. Since each adult costs $4 and each child costs $2, the equation should be
4x + 2y = 20
There are two unknown but only one independent equation. We cannot solve an exact solution for this. One way to solve this is to state all the possibilities. Let's start by assigning values of x. The least value of x possible is 0. This is when no adults but only children bought the tickets.
When x=0,
4(0) + 2y = 20
y = 10
When x=1,
4(1) + 2y = 20
y = 8
When x=2,
4(2) + 2y = 20
y = 6
When x=3,
4(3) + 2y= 20
y = 4
When x = 4,
4(4) + 2y = 20
y = 2
When x = 5,
4(5) + 2y = 20
y = 0
When x = 6,
4(6) + 2y = 20
y = -2
A negative value for y is impossible. Therefore, the list of possible combination ends at x =5. To summarize, the combinations of adults and children tickets sold is tabulated below:
Number of adult tickets Number of children tickets
0 10
1 8
2 6
3 4
4 2
5 0
We are given the expression:
U = E * P
The equality symbol “ = “ means that for all cases, the
value of U and E * P must always be equal. This means that whatever happens on
the left side, must equally happen on the right side.
So what this actually means is that, if we double U so we
must also double the expression E * P, that is:
2 U = 2 (E * P)
However since P stays constant in the process, therefore
only E is changed, hence:
2 U = P * 2 E
So we can see that E is also doubled.
8.60 cm is the answer to your question and i used calculator.net for help
