Assuming boys and girls are equally likely, find the probability of a couple having a baby boyboy when their sixthsixth child is born, given that the first fivefive children were all boysall boys.

Doesn't matter what the first five are. The probability is always 1/2 for the next child. This is like tossing a coin. If you toss a coin 5 times and all the times are tails, what is the probability that the sixth time will be heads. If it's a fair coin, it's 1/2.