There is 12 possible outcomes. also, there is a 3/12 chance of getting a blue marble.
The probability of choosing 3 blue marbles in a row:[tex] \frac{3}{12}* \frac{3}{12} * \frac{3}{12}= \frac{1}{4} *\frac{1}{4}* \frac{1}{4} = \frac{1}{64} =0.015625 [/tex] ( or 1.5625 %)