One day a cat
fell down a well. The well was eighteen feet deep. When the cat tried to climb
out, it found that the well were very damp and slippery. However, with patient
determination it finally managed to climb out.
It took the
cat one minute of climbing to gain three feet. However, after climbing for a
minute, the cat had to rest for a minute before it could go on. During each
minute of rest, the cat slid back two feet.
did it take for the cat to get out of the well?