A blind man is stranded on a deserted island. He has two blue pills and two red pills. Each day, he must take exactly one blue pill and one red pill. If he takes the wrong combination, he will die.
How can he ensure that he always takes exactly one blue pill and one red pill?
Check if you were right - full answer with solution below.
Solution:
Take the pills one at a time, not sorted by color:
- Pick up a pill (any pill, its color is unknown and irrelevant).
- Break it in half.
- Eat one half now; set the other half aside for tomorrow.
- Repeat for all four pills (the 2 blue and 2 red, in whatever order he happens to pick them up).
By the time he's done this to all four pills, he will have eaten exactly one full blue pill's worth and one full red pill's worth today, because each pill, blue or red, contributed exactly half to "today" and half to "tomorrow." The leftover halves automatically form a correct pair for the next day, and the process repeats.
