In a bag there are 15 red and 5 white balls. Two balls are chosen at random and one is found to be red. The probability that the second one is also red is

RR / (RR + RW)

(105 / 190) / [(105 + 75) / 190]

(105 / 190) / (180 / 190)

(105 / 190)(190 / 180)

105 / 180

The probability that both balls are red given one ball is red is 58.33%