Answer:
His actual score is 15
Step-by-step explanation:
Here, we are interested in calculating Wayne’s actual score on the ACT
when we say the scores have being standardized, it means the score was reported in terms of the z-score and not the initial raw scores.
Now, mathematically, for the scores to have a negative z-score, it means it is actually below the mean.
The formula for the z-score or standard score is given below;
z-score = (x - mean)/SD
where in this case, x = ? which is the score we are looking for , z-score = -0.5 , mean score = 18 and standard deviation of the scores = 6
So, substituting these values into the z-score equation, we have;
-0.5 = (x-18)/6
x-18 = 6(-0.5)
x -18 = -3
x = -3 + 18
x = 15
Assuming that the mix disolves into the 20 gallons and doesn't take up space
1:2
x:20
1/2=x/20
multiply btoh sides by 20
10=x
answer is 10 cups of mixture
(x + y)^2 = (x^2 - 2xy + y^2)
First distribute the ^2 on the left side of the equation to each term inside the parenthesis:
x^2+ 2xy + y^2
Now pick one of the variables to solve for and isolate it:
(solving for x)
x^2 + 2xy + y^2 = x^2 - 2xy + y^2
x^2+ 2xy = x^2 - 2xy
2xy = -2xy
-x = x
x = 0
When you solve for y in the equation it will turn out to be 0 as well
just do it like nike said
