three research departments have 8, 7, 6 members respectively. Each department has to select a delegate and alternate how many way can this happen

Question

i dont know what to do for this at all

Answer 1

1st department has 8 choices for the delegate and 7 for the alternate, which has 8*7 = 56 possibilities

 

2nd department has 7 choices for the delegate and 6 for the alternate, which has 7*6 = 42 possibilities

 

3rd department has 6 choices for the delegate and 5 for the alternate, which has 6*5 = 30 possibilities

 

Altogether, there are 56 x 42 x 30 = 70560 ways to elect these officials