A warehouse employs 21 workers on first shift and 18 workers on second shift. Eight workers are chosen at random to be interviewed about the work environment. Complete parts (a) through (d).
(a) find the probability of choosing all first-shift workers
(b) find the probability of choosing all second-shift workers
(c) find the probability of choosing six first-shift workers
(d) find the probability of choosing four second-shift work