Answer:
if she got 4 questions wrong it would be 12
her score if she got x questions wrong it would be 20-2x
Answer:
6
Step-by-step explanation:

250/5=50
20% is same as 1/5
1-1/5=4/5
4/5 is equal to 80%
4 times 50 = 200
Mary kept 200 dollars to herself
15. 40%
16. 20%
17. 50%
18.24%
19. 20%
20. 75%
21. 37.5%
22. 60%
Probabilities are used to determine the chances of events
The probability that event A occurs is 1/2
<h3>How to determine the probability of event A</h3>
From the question, we have the following highlights
- Both events A and B are mutually exclusive
- They are collectively exhaustive
The above means that, the sample space of the events is;
S = {A, B}
So, the sample size is:
n(S) =2
The probability is then calculated as:

This gives

Hence, the probability that event A occurs is 1/2
Read more about probability at:
brainly.com/question/25870256