Out of (2n +1) tickets cosecutively numbered, three are drawn of random, find the probability that the three number on them are in A.P.

Statement 1: Out of 5 tickets consecutively numbered, three are drawn at random. The chance that the numbers on them are in A.P. is 2//15 . Statement 2: Out of 2n+1 tickets consecutively numbered, three are drawn at random, the chance that the numbers on them are in A.P. is 3n//(4n^2-1) .

Out of 21 tickets marked with numbers , from 1 to 21 , three are drawn at random, find the probability that the three numbers on them are in A.P.

If from the numbers 1,2,3… 30 three are drawn at randomm find the probability that they are in G.P.

Out of 3n consecutive integers, three are selected at random. Find the probability that their sum is divisible by 3.

If out of 20 consecutive whole numbers two are chosen at random, then find the probability that their sum is odd.

From set of 1000 cards serially numbered 1,2,3….1000 one card is drawn at random find the probability that the number found is a multiple of 12 and 18

An um contains 30 tickets numbered 1 to 30 two tickets are drawn at random the probability that both the numbers are prime is

Three dice are thrown simultaneously. Find the probability that the sum of the numbers obtained will be 15.

A box contains 7 white and 5 black balls three are drawn at random find the probability that they are not of the same colour when one by one without replacement.

If three numbers are drawn are drawn at random from the frist 30 natural numbers, then the probability that they are in A.P.