153 games were played at a chess tournament with each contestant playing once against each of the others The number of participants is

The number of different ways in which a committee of 4 members formed out of 6 Asians, 3 Europeans and 4 Americans if the committee is to have at least one from each of the 3 regional groups is

A committee of5 is to be formed from 6 boys and 5 girls The number of ways that the committee can be formed so that the committee contains at least one boy and one girl having majority of boys is

If n and  are integers such that  then n c (n‐l, r‐l)=

The least value of the natural number  n satisfying 

 then (n, r)=

 then ‘n’ is

If  = mC₂, then C₂ is equal to -

Students must know how to open expressions like nCr.
Also, the value of n! is n.(n−1).(n−2).....3.2.1.
Combination is used to select r objects from n objects when the arrangement of the objects does not matter.

Twelve students compete for a race. The number of ways in which first three places can be taken, is-

Given the circuit :

Which of the following is equivalent to the above circuit ?
I)
II)
The true statement in the above is / are

The symbolic form of logic of the circuit given below is

The following circuit when expressed in the symbolic form of logic is

For conversion C(graphite)→C(Diamond),the DS is-

Consider the following processes: DH(kJ/mol) ½A→B +150 3B→2C+D–125 E+A→2D+350 ForB+D→E+2C,DHillbe-

Enthalpy change for the reaction, 4H_(g) →2H_2(g) is–869.6kJ The dissociation energy of H–H bond is