試題詳解

8、 The collection efficiency of a cyclone is 45% over the size range 0-5 mm, 80% over the size range 5-10 mm, and 96% for particles exceeding 10 mm. Calculate the total efficiency of collection for the following dust: 50% 0-5 mm, 30% 5-10 mm, 20% above 10 mm.
(A)86%
(B)71%
(C)53%
(D) 65.7%