ISRO2009-19

Question

The switching expression corresponding to $f(\text{A, B, C, D}) = \Sigma(1, 4, 5, 9, 11, 12)$ is

• A. BC'D' + A'C'D + AB'D
• B. ABC' + ACD + B'C'D
• C. ACD' + A'BC' + AC'D'
• D. A'BD + ACD' + BCD'

Comments

Please correct the option A -

it should be BC'D' + A'C'D + AB'D

Answer 1

   =BC'D'+A'C'D+AB'D

So Option A

Comments

I have a question. Why did you ignore pair (4,5) and pair (1,9)?

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suppose u paired 4,5 what about 12 to pair up 12 again u need to pair it with 4 no other possible way

so u have to pair as 4,5 and 4,12 why to pair 4 twice as we have other choice to pair

same as 4,5  1,9 is paired then 11 will be alone

so again it has to be paired with 9 no other way so we try to pair just once if we have choice