Reuben Ngiau Jia Wen's answer to Wee Teck's Junior College 2 H2 Maths Singapore question.
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For part i, you can actually list out the possible scenarios to get the answer since the numbers are small.
Assume A,B, and C are the envelopes with the address on them. Assume a,b and c are the letters to each individual.
In this case, Aa, Bb and Cc indicate that the correct envelope is paired with the correct letter.
The possibilities would as such be as follows:
1. Aa Bb Cc
2. Aa Bc Cb
3. Ab Ba Cc
4. Ab Bc Ca
5. Ac Bb Ca
6. Ac Ba Cb
Out of the 6 possibilities that the letter would be paired with the envelope, 3 of them allow for only 1 person to receive the accurate pair. Therefore, the probability is 3/6 or 50%
Assume A,B, and C are the envelopes with the address on them. Assume a,b and c are the letters to each individual.
In this case, Aa, Bb and Cc indicate that the correct envelope is paired with the correct letter.
The possibilities would as such be as follows:
1. Aa Bb Cc
2. Aa Bc Cb
3. Ab Ba Cc
4. Ab Bc Ca
5. Ac Bb Ca
6. Ac Ba Cb
Out of the 6 possibilities that the letter would be paired with the envelope, 3 of them allow for only 1 person to receive the accurate pair. Therefore, the probability is 3/6 or 50%
Date Posted:
4 years ago
Thx!!
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