Let's suppose the factory produces 1000 bicycles: 600 from assembly line A, 400 from B. 94% of 600=564, 89% of 400=356. So 564+356=920 bicycles (92%) will pass inspection, on average. There are 80 faulty bicycles. 44 of these come off assembly line B. So 44/1000=4.4% is the probability that a bicycle from line B will not pass inspection.