From the first floor to the ninth floor * * * 9- 1 = 8, from the ninth floor back to the third floor * * * 9-3 = 6.

The speed of going upstairs or downstairs is 4/8 = 0.5 minutes per floor. The speed of going up and down the stairs is 0.5 * 2 = 1 minute per floor.

Suppose it takes 6 * 0.5 = 3 minutes to get from the 9th floor to the 3rd floor without going upstairs.

So the time for her to go from the 9th floor is the remaining time = total time-upstairs time-downstairs time = 10-4-3 = 3 minutes.

Therefore, the number of floors to continue upstairs = remaining time/speed of going upstairs and downstairs =3/ 1=3 floors.