Answer:
Step-by-step explanation:
Given that When n is divided by 21, the remainder is an odd number.
i.e. [tex]n=21m+k[/tex] where m is an integer and k a positive integer <21
When n is divided by 28, the remainder is 3
[tex]n=28c+3[/tex], where c is a positive integer
This can be written as
[tex]n=4(7c)+3\\n=7(4c)+3[/tex]
Since n is giving odd remainder when divided by 21,
we get r =3 as n is a multiple of 7 +3
