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.
You divide -15 on both sides to keep the x alone
-240/ -15=16
A negative divided by a negative is a positive so x=16