Olympiad workbook
- Exam
- Olympiad workbook
- Subject
- IOQM
- Chapter
- Permutation and Combination
Olympiad workbook · IOQM · Permutation and Combination
The six sides of a convex hexagon A_1 A_2 A_3 A_4 A_5 A_6 are...
The six sides of a convex hexagon are colored red. Each of the diagonals of the hexagon is colored either red or blue. If is the number of colorings such that every triangle , where , has at least one red side, find the sum of the squares of the digits of .
Correct answer
94
Step-by-step solution
Number of ways such that atleast one side of Number of ways such that atleast one side of is red Number of ways to colour diagonals , \begin{aligned} & A_3 A_6=2^3=8 \\ & \begin{aligned} \therefore \text { Required number } & =8 \times 7 \times 7 \\ & =392=\mathrm{N} \\ \therefore \text { Sum of square of digits } & =3^2+9^2+2^2 \\ & =94 \end{aligned} \end{aligned}$