Answer:
b. Kathy
Step-by-step explanation:
We compare each of their score by how far away from the mean when in term of the standard deviation. Using the following formula

For John he is (85 - 75)/5 = 2.
For Kathy she is (80 - 50)/10 = 3.
Since Kathy is 3 standard deviation better than her class' average, while John is only 2's. We conclude that Kathy did better.
Answer:
Not equivalent
Step-by-step explanation:
Distribute the negative in the parentheses. It basically multiplying everything inside by -1.

add like terms

Not equivalent since the 6x is positive
Answer: helllloooooooooooooo000000oooo
Step-by-step explanation:
X = 80
y = 85
If you look at only the left triangle, you can see that x is part of one of the angles. The 3 interior angles of the triangle add up to 180 degrees, so subtracting the other two angles, you get x + 30 = 110, or x = 80.
The same method can be used for the other triangle to find y.
Answer:
20 green pencils
Step-by-step explanation:
The difference between black and green "ratio units" is 7 -5 = 2. The difference between red and blue ratio units is 3 -2 = 1. The sum of those differences is 2 +1 = 3 ratio units, which represent 12 pencils. Then each ratio unit represents 12/3 = 4 pencils.
The 5 ratio units of green pencils represent 5·4 pencils = 20 green pencils.
_____
If you need an equation, you can use k as the constant of proportionality. Then the sum of differences described is ...
(7k -5k) + (3k -2k) = 12
3k = 12 . . . . simplify
k = 4 . . . . . . divide by 3
5k = 5·4 = 20 . . . . . number of green pencils