probability

A bag contains 26 purple jellybeans, 15 green jellybeans, and 9 yellow jellybeans; these jellybeans are the only items in the bag. If a person reaches into the bag and picks out only purple jellybeans, how many jellybeans would the person have to pick out in order to double the probability that a jellybean picked out of the bag at random would be a green jellybean?
A. 5
B. 15
C. 19
D. 24
E. 25

The total number of jellybeans in the bag was intially 50. And the probability of picking out the green jellybeans was 15/50. But after choosing one purple jellybean the total number of jellybeans in the bag is 49. Hence, the probability of picking out the green jellybeans thereafter is 15/49.
In order to double the probability that a jellybean picked out of the bag at random would be a green jellybean the person should pick 24 more out of 49 jellybeans. Henceforth, the probability of picking out the green jellybeans will be doubled, i.e. 15/25 or 3/5 because the initial pprobability was 15/50 or 3/10.