A school Sixth form chooses at rondom, 3 of the 8 candidates, Ahmed,Barbara,Caleb,Daniel,Enid,Fatima,Georgio and Hannah to represent them on the student council.
(a) Calculate the probability that Barbara, Daniel and Hannah are the three students chosen for the student council.
Two of these eight students are brother and sister.
(b) Calculate the probability that both the brother and sister will be chosen.