Use what you have learned about mutually inclusive and exclusive events. Apply the formula for calculating the probability of events A or B.
Question 1
There are four presidential candidates in a country. A street survey was conducted asking 2,500 registered voters which candidate they will vote for in the coming election. The table summarizes the results of the survey.
Presidential Candidates
Number of Supporters
Candidate 1
250
Candidate 2
1,250
Candidate 3
450
Candidate 4
550
What is the probability of randomly selecting a person who will vote for Candidate 1 or 2?
If 1,000 more voters are surveyed, how many of them will likely prefer Candidate 3 or 4? Explain your answer.
To calculate the probability of randomly selecting a person who will vote for Candidate 1 or Candidate 2, we first need to add the number of supporters for each candidate: 250 (Candidate 1) + 1,250 (Candidate 2) = 1,500.
Then we divide the number of supporters for Candidate 1 or 2 by the total number of voters surveyed: 1,500/ 2,500 = 0.6
So, the probability of randomly selecting a person who will vote for Candidate 1 or Candidate 2 is 0.6 or 60%.
If 1,000 more voters are surveyed, we can expect the same ratio of supporters for Candidate 3 and Candidate 4 to be maintained. Therefore, out of the additional 1,000 voters surveyed, we can expect approximately 40% (450/1,1000) to prefer Candidate 3 and 60% (550/1,1000) to prefer Candidate 4. This would mean around 400 voters will likely prefer Candidate 3 and around 600 voters will likely prefer Candidate 4.