The result of your conversion between cup [US] and fifth appears here
To convert between Cup [US] and Fifth you have to do the following:
First divide (0.000016387064 * 231)/16 / (0.000016387064*231)/5 = 0.3125
Then multiply the amount of Cup [US] you want to convert to Fifth, use the chart below to guide you.
Symbol: c
No description
Symbol: fifth
No description