Question 978044
If you have a box of 12 marbles of 3 different colors, blue, green and red, 4
blue, 4 green, 4 red.  How many ways can you draw two balls of the same color?

<pre>
4C2+4C2+4C2 = 3*(4C2) = 3*(4*3)/(2*1) = 3*12/2 = 3*6 = 18

 1. (b1,b2) 
 2. (b1,b3)
 3. (b1,b4)
 4. (b2,b3)
 5. (b2,b4)
 6. (b3,b4)
 7. (g1,g2)
 8. (g1,g3)
 9. (g1,g4)
10. (g2,g3)
11. (g2,g4)
12. (g3,g4)
13. (r1,r2)
14. (r1,r3)
15. (r1,r4)
16. (r2,r3)
17. (r2,r4)
18. (r3,r4)

Edwin</pre>