natural numbe r does 1 to 25 are written on card and kept in a bag. a card is randomly picked up find the probability of getting (i) a prime numder (ii) a composite number (iii) neither a prime nor composite verify whether the sum of all these probabilities is 1.
Answers & Comments
(I) there are 9 prime numbers between 1 and 25. so the probability of getting a prime number is 9/25.
(ii) 15 numbers are composite between 1 and 25.so the probability is 15/25=3/5
(iii) 1 is the only number which is neither prime nor composite. so the probability is 1/25.
on adding all the probabilities we get 9/25+15/25+1/25=25/25=1.
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