i dont know, my personal thoughts is that I will not do it:)
I believe it's not a function because the input (x) 4 has two outputs(y), 2 and 8.
30% of 250 can be written as 0.3 * 250:
0.3(250) = 75
30% of 250 is 75. Is this what you mean by "compute with percents?"
To get the answer we can use proportion
8 ginger ----------------- 3 fruit
12 ginger ----------------x
Crossmultiply now
8x=12*3 /:8
x=

x=<u />

To not change ratio we have to have 4.5 cups of fruilt juice. We initialy had 3, so we have to add 1.5 cup of fruit juice.
I think the awkward science is quite amusing to me