Comment
Share
Q)

# The number of different ways of distributing 10 marks among 3 questions,each questions carrying atleast 1 mark,is

$\begin{array}{1 1}(A)\;72\\(B)\;71\\(C)\;36\\(D)\;\text{None of these}\end{array}$

• $C(n,r)=\large\frac{n!}{r!(n-r)!}$
$\Rightarrow 9C_7=9C_2$
$9C_2=\large\frac{9!}{2!7!}=\frac{9\times 8\times 7!}{2\times 7!}$
$\Rightarrow 36$