A.
Circumference = π * diameter or
π * 2*radius (diameter = 2 * radius).
So you would divide by π to get the diameter, then divide by 2 to get the radius. So A.
Answer: (B) 6 floors
Step-by-step explanation: Use the equation -3 + 9 to get the amount of floors above ground level.
-3 + 9 = 6
6 floors.
It would be 13... if I did my math right.
Answer:
P(a junior or a senior)=1
Step-by-step explanation:
The formula of the probability is given by:

Where P(A) is the probability of occurring an event A, n(A) is the number of favorable outcomes and N is the total number of outcomes.
In this case, N is the total number of the students of statistics class.
N=18+10=28
The probability of the union of two mutually exclusive events is given by:

Therefore:
P(a junior or a senior) =P(a junior)+P(a senior)
Because a student is a junior or a senior, not both.
n(a junior)=18
n(a senior)=10
P(a junior)=18/28
P(a senior) = 10/28
P(a junior or a senior) = 18/28 + 10/28
Solving the sum of the fractions:
P(a junior or a senior) = 28/28 = 1