She traveled 11 floors.
Explanation:
Wanda stepped onto an elevator at the 8th floor after that comes the 7th floor, 6th floor, 5th floor, 4th floor, 3rd floor, 2nd floor, 1st floor and then ground floor . Hence from 8th floor to ground floor Wanda traveled 8 floors. After ground floor she travels 3 floors more that is -1,-2,-3 . Hence here she travels 3 floors underground. Therefore, the total number of floors traveled by Wanda are 8 floors+3 floors= 11 floors.