Question

A dog breeder currently has 9 breeding dogs. 6 of the dogs have exactly 1 littermate, and 3 of the dogs have exactly 2 littermates. if 2 dogs are selected at random, what is the probability that both selected dogs are not littermates?

Answer 1

Answer:17%

Explanation:

Answer 2

`6+6\cdot1+3+3\cdot2=21` - all dogs


`|\Omega|=21C2=(21!)/(2!19!)=(20\cdot21)/(2)=210\\ |A|=9C2=(9!)/(2!7!)=(8\cdot9)/(2)=36\\\\ P(A)=(36)/(210)=(6)/(35)\approx17\%`