Question:
Let $x$ denote the total number of one-one functions from a set A with 3 elements to a set $B$ with 5 elements and $y$ denote the total number of one-one functions from the set $A$ to the set $\mathrm{A} \times \mathrm{B}$. Then :
Correct Option: , 2
Solution:
$x={ }^{5} C_{3} \times 3 !=60$
$\mathrm{y}={ }^{15} \mathrm{C}_{3} \times 3 !=15 \times 14 \times 13=30 \times 91$
$\therefore 2 \mathrm{y}=91 \mathrm{x}$