A drawer haves two boxes of batteries. One box haves 2 good and 8 bad batteries waiting to be recycled. The other box haves 9 good and 1 bad battery. Neither box is labeled. An unsuspecting person opens drawer and randomly chooses one of these boxes, then tests one of the batteries from the box and it is good. With that knowledge, compute the probability that the person has the chosen the box with 2 good batteries?