The climber descended 543 feet. She starts descending from 553 feet, and keeps descending until she reaches 10 feet. 553-10=543. To check the answer, add 10 to 543, which gets you 553.
It is decreased by a factor of 3. You can determine this by realizing that one inch original equals 3.3 feet, but the equals 1.1 feet, and 3.3/1.1 = 3.