Team \( 'A' \) consists of \( 7 \) boys and \( n \) girls and Team \( 'B' \) has \( 4 \) boys and \( 6 \) girls. If a total of \( 52 \) single matches can be arranged between these two teams when a boy plays against a boy and a girl plays against a girl, then \( n \) is equal to:
