Answer:
It means that there are 2.5 measures of blueberries for every 1 measure of strawberries.
Explanation:
We don't know how Takiko is meauring the berries. She could be counting them, weighing them, measuring their volume, or using some other (less common) measure.
By whatever measure she is using, Takiko has determined that there are 2 measures of strawberries for each 5 measures of blueberries.