A detective finds a room with four numbered switches (1, 2, 3, 4) outside, each controlling one of four distinct colored lights (Red, Blue, Green, Yellow) inside. Switch 1 controls neither Red nor Blue. Switch 2 controls Green. Switch 3 controls Red. Which light does Switch 4 control?
Blue
Switch 2 is Green and Switch 3 is Red. Switch 1 cannot be Red or Blue, so Switch 1 must control Yellow. That leaves Switch 4 to control Blue.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
More logic riddles
Three people check into a hotel room that costs $30 total. They each pay $10. Later, the manager realizes there was a promotion and the room should only cost $25. He gives the bellhop $5 in single dollar bills to return to the guests. On the way up, the dishonest bellhop keeps $2 for himself and gives $1 back to each of the three guests. Now, each guest has paid $9 (total $27), and the bellhop has $2, which equals $29. Where did the missing $1 go?
You have two identical hourglasses: one measures 7 minutes and the other measures 4 minutes. Using both hourglasses simultaneously, how can you measure exactly 9 minutes?
An electric train is traveling due north at 50 miles per hour, while the wind blows from the west at 20 miles per hour. In which direction does the smoke from the engine trail?
What English word becomes shorter when you add two letters to it?
I am worn to look like someone else, and I come off at the end of the party. What am I?
Three suspects are interviewed about a stolen painting. Arthur says, 'Ben did it.' Ben says, 'Carl did it.' Carl says, 'Ben is lying.' Only one statement among the three is true. Who stole the painting?