in a room with 8 people , 5 people have exactly 1 friend in the room and 4 people have exactly 2 friends in the room ( assuming that friendship is a mutual relationship , i . e . if jane is paul ' s friend , paul is jane ' s friend ) . if two individuals are selected from the room at random , what is the probability that those two individuals are not friends ?
"( 5 / 8 ) ( 6 / 7 ) + ( 4 / 8 ) ( 5 / 7 ) if you choose one of the 5 with one other friend , then you have a 6 / 7 chance of not picking their friend 2 nd . if you choose one of the 4 with 2 friends , you have a 5 / 7 chance of not picking one of their friends second . add them up . 30 / 56 + 20 / 56 50 / 56 = 25 / 28 e . 25 / 28"
divide(subtract(subtract(subtract(8, 1), 1), 1), subtract(8, 1))