Before you start to calculate 20 Cups, you should know the conversion rate between Cups and Cubic Inch.
The rate is 1.44575E-14 and the math equation is 20 X 1.44575E-14 = 2.8915E-13 .
Quick conversion chart of Cups to Cubic Inchs
1 Cup to Cubic Inch = 1.44575E-14 Cubic Inch5 Cup to Cubic Inch = 7.22875E-14 Cubic Inch10 Cup to Cubic Inch = 1.44575E-13 Cubic Inch20 Cup to Cubic Inch = 2.8915E-13 Cubic Inch30 Cup to Cubic Inch = 4.33725E-13 Cubic Inch40 Cup to Cubic Inch = 5.783E-13 Cubic Inch50 Cup to Cubic Inch = 7.22875E-13 Cubic Inch75 Cup to Cubic Inch = 1.0843125E-12 Cubic Inch100 Cup to Cubic Inch = 1.44575E-12 Cubic Inch