Replying to Please Help me with my Stats Assignment!

In a group of 1000 people, only 5% have type AB blood.

a) What is the probability that there is a type AB donor among the first 3 people checked?

b)What is the probability that the first type AB donor will be found among the first 6 people checked?

c) What is the probability that there will not be a donor found before the 8th person?

I've been stuck on this for 2 hours now and cannot figure it out. Maybe someone can help me please