Answer: 0.036
Work Shown:
6 red, 6+3+7 = 16 total
A = 6/16 = probability of getting red the first time
after you pick 1 red, there's 6-1 = 5 left out of 16-1 = 15 total
B = 5/15 = probability of getting red the second time
then you repeat: 5-1 = 4 red left out of 15-1 = 14 total
C = 4/14 = probability of getting red the third time
B and C are dependent on A, C is dependent on B. This is assuming we do not put any marbles back.
Multiply out the fractions found
A*B*C = (6/16)*(5/15)*(4/14) = 0.0357 which rounds to 0.036 when rounding to the nearest thousandth.