`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`

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

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

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

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

A positive integer is chosen at random the probability that the sum of the digits of its square is 39 is (A) 1/33 (B) 2/33 (C) 1/11 (D) Zero

In a room,there are 6 couples.Out of them if 4 are chosen at random the probability that they may be 2 couples is (A) (2)/(33) (B) (1)/(33) (C) (1)/(66) (D) (32)/(33)

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

A number x is chosen at random from the numbers -3,-2,-1,0,1,2,3 the probability that |x|<2 is (5)/(7) (b) (2)/(7)(c)(3)/(7) (d) (1)/(7)

Two numbers a and b are chosen at random from the set {1,2,3,..,3n}. The probability that a^(3)+b^(3) is divisible by 3, is

Two numbers a and b are chosen at random from the set {1,2,3,..,5n}. The probability that a^(4)-b^(4) is divisible by 5, is