Answer: C. 
Step-by-step explanation:
Given: Box contains 8 green balls and 4 purple balls.
Total balls = 8+4 = 12
event 1 = first picking green ball
event 2 = second picking purple balls.
As first ball was replaced, that means both events are independent.
Probability that you have selected a green ball and then a purple ball = P(purple ball )
Formula for probability = 
Probability of selecting a purple ball (second pick)= 

The required probability
, so C is correct option.
Answer:
4/5 or 0.8
Step-by-step explanation:
Answer:
if im not mistaken it would be 6
Step-by-step explanation:
because you half the 18
Answer:
Random, because he surveyed 30 <em>random</em> shoppers
Only D is correct, it intersects at 90 degrees so it cant be obtuse or acute and never intersecting would be parallel lines <span />