prob good one

Out of eight marketers and two developers, four people will be chosen at random to occupy the worst office on the floor. What is the probability that at least one of the developers will be chosen? 

Soln

http://www.beatthegmat.com/probability-office-floor-t33427.html

P(choosing atleast 1 Developer) = 1 - P(choosing ALL 4 marketers) 
= 1 - (8/10 * 7/9 * 6/8 *5/7) 
= 1 - 1/3 
= 2/3