Ask Question
4 June, 05:50

Ramone has 5 difficult questions left to answer on a multiple choice test. Each question has 3 choices. For the first 2 of these questions, he eliminated 1 of the 3 choices. find the probability that he will answer the first 2 questions, as well as at least 2 of the 3 remaining questions correctly.

+3
Answers (1)
  1. 4 June, 06:59
    0
    1. a b c

    2. a b c

    3. a b c

    4. a b c

    5. a b c

    then she eliminated 1 choice in 1 and 2, say as follows

    1. b c

    2. a b

    3. a b c

    4. a b c

    5. a b c

    Probability of answering correctly the first 2, and at least 2 or the remaining 3 is

    P (answering 1,2 and exactly 2 of 3.4. or 5.) + P (answering 1,2 and also 3,4,5)

    P (answering 1,2 and exactly 2 of 3.4. or 5.) =

    P (1,2,3,4 correct, 5 wrong) + P (1,2,3,5 correct, 4 wrong) + P (1,2,4,5 correct, 3 wrong)

    also P (1,2,3,4 c, 5w) = P (1,2,3,5 c 4w) = P (1,2,4,5 c 3w)

    so

    P (answering 1,2 and exactly 2 of 3.4. or 5.) = 3*P (1,2,3,4) = 3*1/2*1/2*1/3*1/3*2/3=1/4*2/9=2/36=1/18

    note: P (1 correct) = 1/2

    P (2 correct) = 1/2

    P (3 correct) = 1/3

    P (4 correct) = 1/3

    P (5 wrong) = 2/3

    P (answering 1,2 and also 3,4,5) = 1/2*1/2*1/3*1/3*1/3=1/108

    Ans: P = 1/18+1/108 = (6+1) / 108=7/108
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Ramone has 5 difficult questions left to answer on a multiple choice test. Each question has 3 choices. For the first 2 of these questions, ...” in 📙 Mathematics if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers