Find the probability that both candies will be different colors.

I've already found the probability that it will be, red then blue/blue then orange/ or both blue. So I know how to do these type of problems, but this one is giving me an issue because I'm not sure what formula to use. There are 79 total, but the number of candies aren't equal so there isn't a .33 chance of choosing a different candy each time, because as I said the probability isn't equal to that.

Any ideas?