A firefighter stood on the middle rung of a ladder, spraying water on a burning house. He then climbed up 6 rungs before the heat of the flames caused him to come down 10 rungs. After some minutes he was able to climb 18 rungs to the very top of the ladder. How many rungs did the ladder have?
Answer
29 rungs
The firefighter is standing on the middle rung. He goes up 6 rungs, so he is now at M+6; he now goes down 10 rungs, so he is now at M-4; he goes up 18 rungs, so he is now at M+14=T, 14 rungs from the top, 14 rungs from the bottom and the middle rung. 14+14+1=29!
