The shop offers 100 flavors and she tried 1/4 of the flavors so she had 100*.25 = <<100*.25=25>>25 flavors 2 years ago
Last year she ate double the amount from the previous year so she had 25*2 = <<25*2=50>>50 flavors
2 years ago she ate 25 flavors and last year she had 50 flavors so she has had 25+50 = <<25+50=75>>75 flavors
The shop offers 100 flavors and she has had 75 flavors so she still needs to try 100-75 = <<100-75=25>>25 flavors
#### 25