Question Number 1775 by lakshaysethi039 last updated on 26/Sep/15
$$\mathrm{7}\:{couples}\:{are}\:{there}\:{in}\:{a}\:{society}.\:{The}\:{selection}\:{of} \\ $$$$\:{pairs}\:{are}\:{to}\:{be}\:{done}\:{for}\:{a}\:{mixed}\:{double}\:{badminton} \\ $$$${tournament}.\:{In}\:{how}\:{many}\:{ways}\:{we}\:{can}\:{choose} \\ $$$$\:{these}\:{pairs}? \\ $$