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+13 votes

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?

- 7
- 8
- 9
- 10

+21 votes

Best answer

+14 votes

**Answer : C**

In first Level we need 64 / 8 = 8 Decoder

In second Level to cover 8 select lines Which are coming out from 8 decoder we need 8 / 8 = 1 Decoder

Total =8+1= 9 decoders

+7 votes

Quickest way to solve this type of problems will b:

Number of m bit MUX/DeMUX/Decoder/Encoder to construct N bit MUX/DeMUX/Decoder/Encoder is:

ceil (N-1)/(M-1)

In given problem, (N-1)/(M-1)= 64-1/8-1 =63/7 =9

–9 votes

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