How many 3-to-8 line decoders with an enable input are needed to construct a 6-to-64 line decoder without using any other logic gates?
(A) 7
(B) 8
(C) 9
(D) 10
Answer: (C)
Explanation: 
So total signals in=a, b, c, x, y, z i.e. 6
And total output =8*8=64
hence required decoders (from fig.) = 9Â so ans is ( C) part.
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