This is like the equivalent to a jar with 4 green balls and 6 white balls, where you are picking 3. (The 4 green balls signify the friends from kindergarten.)
You want to solve the probability that the first two balls are green and the third is white.
First draw --> 4 green out of 10 balls --> 4/10 = 2/5
Second draw --> 3 green out of 9 balls --> 3/9 = 1/3
Third draw --> 6 white out of 8 balls --> 6/8 = 3/4
2/5 x 1/3 x 3/4
= 6/60
= 1/10
so the answer is 1/10 (or 10%)
The expression will look like this. (3*6)+4
