Samsung got a good deal on 400 phones. 250 of these phones have 5" screens and the rest have 4" screens. of the 5" screens 140 are silver and the rest are black. out of the 4" screens 80 are silver and the rest are black. if one phone is randomly picked out for a customer. what is the probability that it will: a) be silver or have 5" screen
b) be black or have 4" screen