An organisatiion has n employees. If a committee needs to be fformed from among the employees ncluding at least tow employees and also excluding at least two employees. The number of ways of forming the committee is (A) `2^n-n-1` (B) `2^n-2n-4` (C) `2^n-2n-2` (D) `2^n-2n`

The number of terms in the expansion of (x+1/x+1)^n is (A) 2n (B) 2n+1 (C) 2n-1 (D) none of these

Sum of n terms of series 12+16+24+40+.... (A) 2(2^n -1)+8n (B) 2(2^n-1)+6n (C) 3(2^n-1)+8n (D) 4(2^n-1)+8n

Let A={1,2,..., n} and B={a , b }. Then number of subjections from A into B is n_P_2 (b) 2^n-2 (c) 2^n-1 (d) nC2

The sum of first n odd natural numbers is 2n-1 (b) 2n+1 (c) n^2 (d) n^2-1

Number of ways of forming a team consisting of at least 2 and atmost (n - 2) students from n students is

The mean of first n odd natural number is (a) (n+1)/2 (b) n/2 (c) n (d) n^2

Find sum of sum_(r=1)^n r . C (2n,r) (a) n*2^(2n-1) (b) 2^(2n-1) (c) 2^(n-1)+1 (d) None of these

The arithmetic mean of 1,2,3,...n is (a) (n+1)/2 (b) (n-1)/2 (c) n/2 (d) n/2+1

The arithmetic mean of 1,2,3,...n is (a) (n+1)/2 (b) (n-1)/2 (c) n/2 (d) n/2+1

Straight lines are drawn by joining m points on a straight line of n points on another line. Then excluding the given points, the number of point of intersections of the lines drawn is (no tow lines drawn are parallel and no these lines are concurrent). a. 4m n(m-1)(n-1) b. 1/2m n(m-1)(n-1) c. 1/2m^2n^2 d. 1/4m^2n^2