a student in a big city lives on the 44th floor of her building. on rainy days, when she gets home from school, she takes the elevator all the way up to her floor. but on sunny days, she goes up to floor 20 and walks the rest of the way. why?

The reason the student takes the elevator all the way to the 44th floor on rainy days but only goes up to the 20th floor and walks the rest on sunny days is likely because she is short and cannot reach the button for the 44th floor in the elevator. On rainy days, she carries an umbrella which she can use to press the button for the 44th floor. On sunny days, without the umbrella, the tallest button she can reach is for the 20th floor, so she walks the rest of the way up.