Another good one but.... Spoiler below!

You guys need to review the dartboard. The answer requires you to multiply from the code in the book but the correct number to open the door does not match the math according to the book you have. 4x2 (double score) is 8 and not 12 which is 4x3.
If thats the case then the 9 would need to be multiplied by 2 or 3 also and it wasnt required for the answer. Please learn your math.

SlasH1313 about Diamond Penthouse Escape 2