A goldsmith has a bag, which contains some colourful stones. It contains 5 White and 10 Black stones. There is another bag which contains 4 White and 6 Black stones. One stone is to drawn from either of the two bags. What is the probability of drawing a White stone?

\(\frac{11}{30}\)

Probability of choosing one bag = \(\frac{1}{2}\)

Probability of White stone from 1st bag = \(\frac{1}{2}\) × \(\frac{^{5} \mathrm{ C }_1}{^{15} \mathrm{ C }_1}\) =\(\frac{1}{6}\)

Probability of White stones from 2nd bag = \(\frac{1}{2}\) × \(\frac{^{4} \mathrm{ C }_1}{^{10} \mathrm{ C }_1}\) = \(\frac{1}{5}\)

∴ Reqd. probability = \(\frac{1}{6}\) + \(\frac{1}{5}\) = \(\frac{11}{30}\)

Hence, option C is correct.