Third of Many: Rubies
"abdul the jeweler has in his home three chests of drawers; each chest contains two drawers. in one of the chests, each drawer contains a ruby. in another of the chests, each drawer contains an emerald, and in the third chest, one drawer contains a ruby and the other drawer contains an emerald. suppose you pick one of the three chests at random and open one of the drawers and find a ruby. what is the probability that the other drawer in the same chest will also contain a ruby?"
this one's hard.
write your answers in the comments and i'll confirm the correct one.
don't read the comments unless you want the answer.