Please answer with some work shown!

- Kirstin is decorating her bedroom wall with photographs.
She has 36 photographs of family and 28 photographs of friends.
She wants to arrange the photographs in rows so that each row
has the same number of photographs, and photographs of family
and photographs of friends do not appear in the same row.
a. How many rows will there be if Kirstin puts the greatest possible
number of photographs in each row?

b. How many photographs will be in each row?