Math, asked by poornabalu, 1 year ago

There are 5 multiple choice questions with 4 posiible answers each out of which only one is correct.What is the probability of getting atleast 3 answers correct?

Answers

Answered by sami99
1
Total no of questions=5 Possible answers=20 (5×4) Total correct answers=5 (as there is only one ans correct in each ques) So the probability of getting at least 3 ans correct will be= 3/20 : )

sami99: Yes....which is better.....although both r the exact same....
poornabalu: its wrong....sry
sami99: How is it wrong ?can u pls give the correct ans....
poornabalu: i too dont knw! :(
poornabalu: Here is the answer.....5c3*(1/4)^3 * (3/4)^2 + 5c4*(1/4)^4 * (3/4) +5c5 *(1/4)^5 =53/512...........
Answered by joshinrexy22
1
No. of MCQ questions = 5
No. of correct answer in 1 MCQ question = 1 out of 4 options
No. of possible answers total = 5 * 4 = 20
No. of total correct answers = 5/20
Probability of getting 3 answers correct is 3/20

joshinrexy22: if u find it useful please mark as best
poornabalu: no.......wrng answer
joshinrexy22: how?
poornabalu: its a question asked in interview! i remember only the denominator values...its like 512 for 3 options and 256 for a single option
poornabalu: Here is the answer.....5c3*(1/4)^3 * (3/4)^2 + 5c4*(1/4)^4 * (3/4) +5c5 *(1/4)^5 =53/512
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