Question

A bowl contains 8 blue marbles and 5 green marbles. Elizabeth randomly draws 4 marbles form the bowl. she does not replace the marbles after each draw. what is the probability that she draws 1 blue marble and 3 green marbles?

A. 4/13
B. 13/143
C. 4/143
D. 16/143

Answer 1

since she puts the marbles back, these events are dependent on each other
so
probability=(desired outcomes)/(total possilbe)
8+5=13=total
probailigy of blue=8/13
gree=5/13
so if she draws theem in that order then
8/13 times (since there is one less, -1 of 13) 5/12 times (assume 1 grreen was drawn from previus drawing) 4/11 times (assume as previus) 3/10


so
8/13 times 5/12 times 4/11 times 3/10=4/143=C

the answer is C 4/143