When she picks 1/4 of the number of tomatoes, she goes home with 1/4*100 = <<1/4*100=25>>25 tomatoes.
The total number of tomatoes remaining will be 100-25 = <<100-25=75>>75 tomatoes.
After picking 20 more tomatoes the following week, the number of tomatoes remaining is 75-20 = <<75-20=55>>55 tomatoes.
The next week she picks twice the number she picked the previous week, that is 20*2 = <<20*2=40>>40 tomatoes.
The total number of tomatoes remaining after the final picking is 55-40 = <<55-40=15>>15 tomatoes.
#### 15