1. An airplane took off and reached an altitude of 10,000 feet. Due to a storm, it had to decrease
it's altitude by 2,500 feet. What is the
airplane's current altitude?
a. 25,000
b. 500
c. 7,500
d. 12,500

Please answer it will help me a lot

1foot = 12 inches; 1 yard = 3 feet

You're locked out of your house. the only open window is on the second floor, 25 feet above the ground. there are bushes along the edge of the house, so you will need to place the ladder 10 feet from the house. what length ladder do you need to reach the window?

How is this equation completed? i cannot find any examples in the book.