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.
A square with the same perimeter as a rectangle will have larger area.
However, 42 is not divisible by 4, so we can do 10 by 11.
Length = 11, Width = 10, Area = 110
42 / 4 = 10.5
Length and Width = 10.5, Area = 110.25
Answer:
5.98
Step-by-step explanation:
384 is between 380 and 390