https://m.facebook.com/groups/1675844779330612?notif_t=group_activity&ref=m_notif

Hi. i think pigeonhole principle will be applied here.. two possibilities=> i) Mutual Friend,ii)stranger (let K be the number of possibilities K=2 here) now 6 people is there so N=6. ceil(N/K)=ceil(6/2)=3

atleast 3 of them will have to be either friend or stranger This is the approach