For the binary operation multiplication modulo 10(×10) defined on the set S = {1, 3, 7, 9}, write the inverse of 3.
From the definition of multiplication modulo
a*b = (m is the base of the modulo)
Here the base is 10 and the set is S = {1,3,7,9}
So, We can make the composition table as :-
The identity element is 1.
So, the inverse element of 3 is 7.