If S={1,2,3,...,20} .If 3 numbers are chosen at random from S .The probability for they are in A.P is `I` then `38I-1` is

S={1,2,3,....11} if 3 numbers are chosen at random from S, the probability for they are in G.P.

S={1,2,3,....20} if 3 numbers are chosen at random from S, the probability for they are in A.P.is (A) (3)/(38) (B) (35)/(33) (C) (33)/(35) (D) (1)/(38)

Three numbers are chosen at random from 1 to 15. The probability that they are consecutive is

Four numbers are chosen at random from {1,2,3,......,40}. The probability that they are not consecutive is

Three numbers are chosen from 1 to 20. Find the probability that they are consecutive.

Out of 20 consecutive numbers, two are chosen at random, the probability that their sum is odd is

From 4m+1 tickets numbered as 1,2 ,….4m+1…. Three tickets are chosen at random. Find out the probability that the numbers are in A.P. with even common difference.

Three numbers are chosen at random from numbers 1to 30.Write the probability that the chosen number are consecutive.

Let S = {1, 2, 3, ..., 100). Suppose b and c are chosen at random from the set S. The probability that 4x^2+bx+c has equal roots is