I’m a little confused by the question and the problem, is there a picture of the problem you could add?
Answer:
6.25%
Step-by-step explanation:
Total = 1 ; as a decimal
1/2 = skittles
1/4 = M&Ms
Skittles +M&Ms = 1/2 + 1/4 = 3/4
Remainder = 1 -
Remainder = 
Sour patch = 
As a percentage , multiply 1/16 by 100 and it becomes 6.25%
The prisoners could do a pattern that could signal who has already been in the room. So for example, one light off, both lights off, one light on, both lights off. But with left and right lights to make the sequence last as long as possible. Then after that sequence to have the last one be the signal that everyone has been in there. I dunno this is tricky lol