I think the second one is 18/350 (Guessing I need to simplify that, so 9/175??)
you made a slight mistake
it says specifically Type B printer so 18 + 102 = 120 printers in total for Type B printers
18/120 = 9/60 = 3/20
Ty but what about the first one?
EDIT: oh...>.<
p(type b-defective)=18/120
p(type b-defective)=3/20
Thank you both! But what about the first question? >.<