A) the elevator started at floor 12
B) it moved down 8 floors to floor 4
C) it stopped moving
D) it moved up 2 floors from floor 8 to floor 10
Answer:

Step-by-step explanation:
Basically, if you want to find the probability of getting either outcomes, you will need to subtract the probability of getting neither outcomes in the question. The probability for both outcomes are 7/9 and 5/9 respectively. You will have to multiply to get the probability of getting both of the non-desired outcomes. Hence, it gives the equation above
Sales increased 50% last year, from $5,000 to $10,000. When sales dropped from $10,000 to $5,000 this year, sales decreased 50%