SHIP LADDER

Subject: SHIP LADDER Tue 09 Dec 2014, 9:08 pm

A ladder hangs over the side of a ship anchored in a port. The bottom rung touches the water. The distance between rungs is 20 cm and the length of the ladder is 180 cm. The tide is rising at the rate of 15 cm each hour.
When will the water reach the seventh rung from the top?

Subject: Re: SHIP LADDER Tue 09 Dec 2014, 9:42 pm

This is a nice nonsense. Each guest paid $9 because they gave $30 and they were given back $3. The manager got $25 and the difference ($2) has the bellboy. So it is nonsense to add the $2 to the $27, since the bellboy kept the $2.