Use what you have learned about mutually inclusive and exclusive events.

Apply the formula for calculating the probability of events A or B.



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


Part 1: What is the probability of randomly selecting a person who will vote for Candidate 1 or 2?

(2 points)
Responses

2502500
250 over 2500

15002500
1500 over 2500

10002500
1000 over 2500

12502500
1250 over 2500
Question 2
Part 2: If 1,000 more voters are surveyed, how many of them will likely prefer Candidate 3 or 4? Be sure to use the NEW TOTAL amount of voters to calculate your answer. Show your work and explain your answer.(2 points)
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1 answer

Part 1: Probability of Selecting a Person Who Will Vote for Candidate 1 or 2

To find the probability of selecting a person who will vote for Candidate 1 or Candidate 2, we first need to determine the total number of supporters for these candidates:

  • Supporters for Candidate 1: 250
  • Supporters for Candidate 2: 1,250

So, the total number of supporters for Candidates 1 and 2 is:

\[ 250 + 1,250 = 1,500 \]

The total number of surveyed voters is 2,500. Therefore, the probability \( P(A \text{ or } B) \) of selecting a person who will vote for Candidate 1 or Candidate 2 is:

\[ P(A \text{ or } B) = \frac{\text{Number of supporters for Candidates 1 and 2}}{\text{Total number of voters}} = \frac{1,500}{2,500} \]

This simplifies to:

\[ P(A \text{ or } B) = \frac{1,500}{2,500} = \frac{3}{5} \]

Among the given options, the correct response is:

1500 over 2500


Part 2: Preference for Candidate 3 or 4 Among Additional Voters

Now, if 1,000 more voters are surveyed, we must find the new total number of voters and then determine how many of the new participants are likely to prefer Candidates 3 or 4.

Current Supporters:

  • Candidate 3: 450 supporters
  • Candidate 4: 550 supporters

Total Supporters for Candidates 3 and 4:

\[ 450 + 550 = 1,000 \]

New Total Number of Voters:

\[ 2,500 \text{ (original voters)} + 1,000 \text{ (new voters)} = 3,500 \text{ (total voters)} \]

Assuming the same proportions hold, the percentage of voters who support Candidates 3 and 4 based on the original survey can be calculated:

The proportion of supporters for Candidates 3 and 4 out of the original total is:

\[ \frac{1,000}{2,500} = 0.4 \text{ (or 40%)} \]

Therefore, if we assume the same percentage applies to the new group of 1,000 voters:

\[ \text{Supporters for Candidates 3 and 4 among the new voters} = 1,000 \times 0.4 = 400 \]

Thus, it is likely that 400 out of the 1,000 new voters will prefer Candidates 3 or 4.