Câu 1. Một nhà máy sản xuất bóng đèn có hai phân xưởng I và II. Biết rằng phân xưởng II sản xuất gấp 4 lần phân xưởng I, tỷ lệ bóng hư của phân xưởng I là 10%, phân xưởng II là 20%. a) Một người mua ngẫu nhiên một bóng đèn từ nhà máy. Tính xác suất để người đó mua được một bóng hư. b) Mua 1 bóng đèn của nhà máy thì được bóng hư. Tính xác suất để bóng này do phân xưởng I sản xuất

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