If Mary spent half of her allowance the equation will begin with 1/2x or 0.5x where x is her allowance and 0.5 is half of her allowance spent. Mary also earned 7 dollars by washing the car so this will be added to her allowance spent.
The problem says that after Mary has spent half of her allowance at the movies she was left with 18 dollars so that means that the equation must be equal to 18.
The equation you want to set up is
0.5x+7=18
Where, 18-7=11
0.5x=11
11/.5 = x
x = $22
Thus, Mary has a weekly allowance of 22 dollars.
When you are looking for a unit rate in a graph you want to know how much the dependent (y) variable will increase by when the independent (x) variable is increased by one
The perimeter of a rectangle is 30 inches. If its length is three times its width, find the dimensions. 30 inches=2(L+W) Divide each side by 2. 15 inches=L+W Substitute for L.
1.2 is the answer to your question.