Question

Suppose a jar contains 6 red marbles and 13 blue marbles. If you reach in the jar and pull out marbles at random at the same time, find the probability that both are red

Answer 1

what's the probability that one of the marbles you grab is red:

`P(R)=(6)/(13+6)=(6)/(19)`

now what's the probability of doing it again but with one less red marble:

`P(R)=(5)/(13+5)=(5)/(18)`

Now,

`P(RR)=(6)/(19)*(5)/(18)=(5)/(57)`

The answer is 5/57