Number of Input and Output lines

Question

A input function can take values {0,1,2,4,6,7} and the output can take {0,2,4,6}.

Then how many bits (lines) are required for input and output ?

My doubt is: Since only 4 different states are required to be represented (for output) , so why not use only 2 bits?

Comments

I think 3 bits are required

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it is just a combinationation circuit.

last output will be 6, represented as 110 in 3 bits.

Answer 1

Answer:

Bits required for input : 3 bits

Bits required for output : 3 bits.

 That's it.

Comments

Does the question mean how many bit are required to represent input and output?

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yes. Plz re-read line in the question :

Then how many bits (lines) are required for input and output ?