A bag contains tickets numbered 1-30. 3 tickets are drawn randomly. What is the probability that maxm. no. of selected tickets exceeds 25?

Question

A bag contains tickets numbered 1-30. 3 tickets are drawn randomly. What is the probability that maximum no. of selected tickets exceeds 25?

Answer 1

Let A be the event that none of the selected tickets bear number exceeding 25.

Then required probability

Now, total numbers of ways of drawing three tickets out of 30 is ³⁰C₃

∴ Total number of elementary event = ³⁰C₃

and three tickets are drawn from tickets bearing number 1 to 25 can be done in ²⁵C₃ ways

∴ Favourable number of elementary event = ²⁵C₃