two chips are drawn at random without replacement. there is 7 red chips, 5 blue chips, and 3 white chips what is the probability of getting

The probability is given by

C(7,2) / C(15,2)  = 1/5 or 20%

Another way to see this is that we have a 7/15 chance on the first draw of getting a red chip and a 6/14 chance on the second draw of getting a red one.

So

7/15  x  6/14  = 

7/14 x 6/15 =

1/2  x 2/5  =

1/5