She takes 2 candies, and must get 1 sweet and one sour.
The first candy must be sweet followed by a candy that is sour or the first must be sour followed by a sweet one.
Probability of first candy being sweet: p(first sweet) = 4/6
Probability of second candy being sour: p(second sour) = 2/5
Combined probability: 4/6 * 2/5 = 8/30
Probability of first candy being sour: p(first sour) = 2/6
Probability of second candy being sweet: p(second sweet) = 4/5
Combined probability: 2/6 * 4/5 = 8/30
Add the two probabilities: 8/30 + 8/30 = 16/30 = 8/15
Answer: 8/15
