Answer:
There is a 0% chance that the offspring will be both short and white flowers.
Explanation:
For this we are going to go in and use the Punnett squares. Let´s identify the dominant and recessive genes.
Tall Flowers are Dominant - T(capital for dominance)
Short Flowers are Recessive - t(lowercase for recessiveness)
Blue Flowers are Dominant - W(Capital for dominance)
White Flowers are Recessive - w(Lowercase for recessiveness)
Let´s set up our chart with the information that we have. Its easy to draw the chart, but we need to understand the genes, and make sure that everything is okay!
There is a picture that I took of the chart on the bottom of the page. You can see the dominance of the Tall gene, and the Dominance of the Blue gene. Because none of the offspring have a chance of being short of white, that makes it impossible to have a percentage any higher than 0%.
UNLESS there is a clear mishap or genetically mutated gene in the flower. We never know! I really hope this helped!