1. **State the problem:** We have a box with 2 white and 3 blue marbles, total 5 marbles. 2. We pick two marbles one after the other without replacement. 3. We want the probability that the two marbles picked are of different colors. 4. Total ways to pick 2 marbles from 5 is $$\binom{5}{2} = \frac{5 \times 4}{2} = 10.$$ 5. Calculate the number of favorable outcomes (one white and one blue): - Number of ways to pick 1 white from 2: $$\binom{2}{1} = 2$$ - Number of ways to pick 1 blue from 3: $$\binom{3}{1} = 3$$ - Total favorable pairs: $$2 \times 3 = 6$$ 6. Probability of picking two marbles of different colors is $$\frac{6}{10} = \frac{3}{5}.$$ 7. **Answer:** (b) $$\frac{3}{5}$$