The answer is 62.
After you took out one ball the total number has to be dividable by 3 because red balls are 2 times as the blue balls.
consider what left by dividing 3 for all these numbers:7 (1); 10 (1); 13 (1); 18 (0); 28 (1); 31 (1); 46 (1); 62 (2).You have to take 62 off so that the sum is dividable by 3.
If you really want to know what is red and what is blue,the answer is not clear because there are two possibilities:
A:red:10,18,28,46; blue:7,13,31
B:red:7,18,31,46; blue:10,13,28
Yours,
Ping