Question

If$A=\{1,2,3\},B=\{p,q,r,s\}$ then arrange the following in ascending order
a. number of functions from $A$ into $B$
b. number of constant functions from $B$ to $A$
c. number of one one functions from $A$ into $B$
d. number of onto functions from $A$ into $B$

• A. $d,b,c,a$
• B. $b,c,a,d$
• C. $c,b,d,a$
• D. $d,a,b,c$

Answer 1

Answer: (A)

$d,b,c,a$

(a) Number of functions from $A$ to $B=4\times 4\times 4=64$

(b) No of constant functions from $B$ to $A=3$

(c) No of one - one functions from $A$ to $B=4!=24$

(d) No of Onto functions from $A$ to $B=0$