Concept: The question tests on the basics of Counting
Solution:
Number of Red Marbles = (2 / 5) * 30 = 12
Number of Blue Marbles = 30 - 12 = 18
Probability = Favourable / Total Outcomes
Picking without replacement, and we need to find the probability that the second marble is red.
Case 1: First Red and then 2nd Red: = (12 / 30) * (11 / 29) = 22/145
Case 2: First Blue and then 2nd Red: = (18 / 30) * (12 / 29) = 36/145
Since these are 2 separate events (Case 1 or Case 2), the required probability is the addition of the 2 probabilities = 22/145 + 36/145 = 58/145 = 2 / 5 (Both divisible by 29)
Option D