To determine the number of animals in each pack, we need to understand each statement in the problem since these are key to obtaining the correct answer.
number of packs = 3
number of animals given to sister = 6
number of animals left = 9
total number of animals = 6+9 = 15
It is said the in each pack there is an equal number of animals. Therefore,
Number of animals per pack = 15 / 3 = 5 animals