Question

What is the minimum number of colours required to fill the spaces in the following diagrams without the adjacent sides having the same colour?

• A. $3$
• B. $4$
• C. $6$
• D. $8$

Answer 1

Answer: (B)

$4$

fill the triangle with numbers.
any adjacent side with next number
to a portion which is not in touch with previously filled number, can be filled with the previous number.
B option