Q. 144.0( 2 Votes )

Marks obtained by 90 students of Class IX in a test are given below:


Out of these students one is chosen at random. Find the probability that the chosen student obtains

(i) less than 20% marks (ii) 80% of more marks

(iii) 60% or more marks

Answer :

Total number of students : 90


Number of students who scored less than 20% : 8


Number of students who scored more than 80% : 9


Number of students who scored more than 60% : 35


Probability P() =


(i) Let P(20) be probability of students who scored less than 20%


P(20) =


(ii) Let P(80) be probability of students who scored more than 80%


P(80) =


(iii) Let P(60) be probability of students who scored more than 60%


P(60) =


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