Find the sum of all positive odd numbers up to 98.

The sum of all consecutive odd numbers from 1 to 25 is:

A lift carrying 50 passengers from the ground floor of a 100-storeyed building moves upward. The lift stops at the 1st, 2nd, and 3rd floor, then skips the 4th floor, stops at the 5th, 6th, and 7th floor, skips the 8th floor, and so on. At each stopping floor, passengers get discharged in a repeating pattern of 2, 3, 3, 2, 3, 3, ... (i.e., 2 passengers at the 1st stop, 3 at the 2nd stop, 3 at the 3rd stop, 2 at the 4th stop, and so on). At which floor does the lift become empty?