Posted by mathstudent205 on Monday, January 14, 2013 at 8:38am.
Hello everybody!
May I ask you a big favor?
I need help.
What I have is:
A bag contains marbles of three different colors with at least three marbles of each color.
Three marbles are randomly selected, without replacement. How many different color combinations are possible?
I tried to use Combinatorial Calculator here:
numberempire com
And I've got : 10
Seems like it is the right answer, because textbook shows me the same..
But I want to understand the way of solving it.
Please show me step by step solution or the formula.
Thanks in advance.

Math  Reiny, Monday, January 14, 2013 at 9:08am
It said, "How many different color combinations are possible" , so as long as there are 3 different colours available, the number of actual marbles does not matter.
Suppose we have R, B , and G for our colours.
So we could have:
RRR
RRB
RRG
BBB
BBR
BBG
GGG
GGR
GGB
RBG > which makes 10
or
all the same = 3
2 of one, the third different = (3x1)x2 = 6
all different = 1