Question

A thief starts climbing up a building 30 ft tall. Each hour it climbs 4 feet. And slips back 3 ft. How much time would it take the thief to reach the top of the building

Answer 1

Since the thief gains 4 feet of progress every hour but loses 3 feet within the same hour, his progress can be shown as:

P=4-3

Therefore his progress per hour is 1 foot.  Multiply that by the number of feet he has to climb and your answer is that it will take him 30 hours.