Probability that the first ball was red and the second blue

 A bag contains only \(x\) red balls, \(y\) blue balls and \(z\) yellow balls.

One ball is taken out at random; this ball is then placed back in the bag. Then once again, a ball is taken out at random from the bag.

If the balls are identical in all respects except colour and are well mixed, what is the probability that the first ball was red and the second blue?

• \(\dfrac{(x+y)}{(x+y+z)}\)
• \(\dfrac{(x+y)}{(x+y+z)^{2}}\)
• \(\dfrac{xy}{(y+z)(x+z)}\)
• \(\dfrac{xy}{(x+y+z)(x+z)}\)
• \(\dfrac{xy}{(x+y+z)^{2}}\)