Question

Cards with number 11,12,13………100are placed in a box one card is drawn find probability of getting aprime number less than 30

Answer 1

Answer: 1/15

find the total cards in the box by using AP formula i.e. an=a+(n-1)d

a=11, d=1, an=100 (sub in the formula)

11+(n-1)d=100

11+n-1=100

n=90

hence total cards in box=90

(acc to ques.)prime no's between 11 and 30:-

11, 13, 17, 19, 23, 29 (total are 6)

hence, p(prime no less than 30)= 6/90

= 1/15

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