B = Black
G = Green
Y = Yellow
The total number of ways that he can pick a pic are 3 * 3 * 3 = 27 ways
If he picks Black for the first pic The number of successful ways that he picks two in a row are
B B G
B B Y
B G G
B Y Y Total 4 ways.
If he picks Green first the number of ways are
G G B
G G Y
G B B
G Y Y Total 4 ways
If he picks Yellow first then the number of ways are
Y Y B
Y Y G
Y B B
Y G G And again there are 4 ways
In all we have 12 successes
There are 12/27 chances of picking 2 pics in a row that are the same color.
4/9 <<<< answer
There must be some way to represent this using combinations, but I'm not sure what it is. However this method works.
