Question: James builds a 20 story building.  The first 10 stories are each 12 feet tall each.  The remaining floors are each 3 feet taller.  How tall is the building?
Solution:
The first 10 floors are 10*12=120 feet
There are a remaining 20-10=10 stories
They are each 12+3=15 feet
So those stories are 15*10=150 feet
So the total height is 120+150=270 feet
Answer: 270