Step 1 :Find the total number of ways to choose one boy and one girl: \(8 \times 10 = 80\)
Step 2 :There is only 1 way to choose the brother and sister
Step 3 :Calculate the probability: \(\frac{1}{80}\)
Step 4 :\(\boxed{\frac{1}{80}}\) is the probability that the brother and sister are chosen