how is the minimum number of NOR gates required is 5?

Question

Comments

to find no of NOR gates required for an SOP expression, u better find equivalent POS expression which is

$(\bar{B} +\bar{C} )(B +C )$

double negate the expression and u’ll get the min no of NOR gates to be 5.

Answer 1

You might have overlooked that the positioning in Kmap is 00 01 10 11, while its usually 00 01 11 10

So you should be getting 2 pairs (here) instead of a quad (usual):

B’C + BC’

i.e XOR gate

for XOR gate 5 XNORs are required.