Example:
15 Gm/L = 56781176.751004 kilometer per US gallon
1 Gm/L = 3785411.7834 kilometer per US gallon | 1 kilometer per US gallon = 2.641721e-7 Gm/L
Conversion Steps:
15 × (1e+9 / 264.1720524) = 56781176.75100441