First divide 12 by 10 to get the height of one story on the blueprint, which is 1.2.
Then divide 25 by 2 to get how many feet equal 1 inch (12.5)
Lastly multiply 12.5 by 1.2 to get how many feet equal 1.2 inches.
The answer would be:
The actual height of one story is 15 feet.