A teacher is to form two groups of 3 students from a class of 3 boys and 4 girls.
Three of the girls, Ivy, Tamie and Cassy are good friends.
Find the probability that either Ivy or Tamie is in the same group as Cassy.
You are ignoring most of the given information.
And you are misreading the question.
There are 7 students.
We select 6 of them: . ways.
Then we divide them into two groups of 3 students: . ways.
. . Hence, there are: . possible groupings.
How many groupings have: . in the same group?