The least value of the natural number $n$ satisfying $C(n, 5) + C(n, 6) > C(n+1, 5)$ is

The set of solutions satisfying both $x^2+5x+6 \geq 0$ and $x^2+3x-4 < 0$ is

At $27^{\circ} C$,a closed vessel contains a mixture of equal weights of helium (mol. wt. = $4$),methane (mol. wt. = $16$) and sulphur dioxide (mol. wt. = $64$). The pressure exerted by the mixture is $210 \ mm$. If the partial pressures of helium,methane and sulphur dioxide are $p_1, p_2$ and $p_3$ respectively,which one of the following is correct?

Which of the following groups of transition metals are known as coinage metals?

The lines represented by the equation $x^2-y^2-x+3y-2=0$ are :

Which of the following molecules does not have a linear arrangement of atoms?