If a set P contains 5 elements and the set Q contains 8 elements, then the number of one-one functions from A to B is :
Answer & explanation
Correct answer: option 2
No. of elements in P = p = 5
No. of elements in Q = q = 8
p → contains m elements
q → contains n elements
then no. of one one functions from p → q
$\equiv { }^n P_m = { }^n C_m \times m$ !
No of one one fractions from P → Q is ${ }^8 P_5={ }^8 C_5 \times 5$ !