Answer
$\dfrac{1}{8}=0.125$
Work Step by Step
The possible outcomes are: $GGG,GGB,GBG,BGG,GBB,BGB,BBG, BBB$, which is $8$ outcomes
Only $1$ outcome favors the given event..
We know that $\text{probability}=\dfrac{\text{number of favorable outcomes}}{\text{number of all outcomes}}=\dfrac{n(F)}{n(S)}.$
Hence,
$\text{probability}=\dfrac{1}{8}=0.125$
