Answer:
55%
the percent decrease of the sale price from the regular price is 55%
Step-by-step explanation:
Percentage decrease is the percentage change in the sales price (regular and new)
Percentage decrease %∆P = ∆P/Pr × 100%
∆P = change in sales price = $135 - $60.75
Pr = regular price = $135
Substituting the values;
%∆P = (135-60.75)/135 × 100%
%∆P = 55%
the percent decrease of the sale price from the regular price is 55%
Answers:
The z scores are approximately:
- Care of Magical Creatures: z = 0.333
- Defense Against the Dark Arts: z = 0.583
- Transfiguration: z = -0.263
- Potions: z = -0.533
From those scores, we can say:
- Best grade = Defense Against the Dark Arts
- Worst grade = Potions
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Further Explanation:
We'll need to convert each given score to a corresponding standardized z score.
The formula to use is
z = (x - mu)/sigma
where,
- x = given grade for each class
- mu = mean
- sigma = standard deviation
Let's find the z score for the Care of Magical Creatures class
z = (x - mu)/sigma
z = (3.80 - 3.75)/(0.15)
z = 0.333 approximately
Repeat this process for the Defense Against the Dark Arts score.
z = (x - mu)/sigma
z = (3.60 - 3.25)/(0.60)
z = 0.583 approximately
And for the Transfiguration class as well
z = (x - mu)/sigma
z = (3.10 - 3.20)/(0.38)
z = -0.263 approximately
The negative z score means his grade below the average, whereas earlier the other scores were above the average since he got positive z scores.
Now do the final class (Potions) to get this z score
z = (x - mu)/sigma
z = (2.50 - 2.90)/(0.75)
z = -0.533 approximately
This grade is below average as well.
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To summarize, we have these z scores
- Care of Magical Creatures: z = 0.333
- Defense Against the Dark Arts: z = 0.583
- Transfiguration: z = -0.263
- Potions: z = -0.533
Harry did his best in Defense Against the Dark Arts because the z score of 0.583 (approximate) is the largest of the four z scores. On the other hand, his worst grade is in Potions because -0.533 is the lowest z score.
Answer:
6 liters
Step-by-step explanation:
Let x represent the amount of pure concentrate used to make the punch. Then the total amount of concentrate in the punch is ...
0.20·10 +1.00x = 0.50(10+x)
x +2 = 0.5x +5 . . . . . eliminate parentheses
0.5x = 3 . . . . . . . . . . .subtract 2+0.5x
x = 6 . . . . . . . . . . . . . multiply by 2
6 liters of pure concentrate must be added to make a 50% punch.
