You need to look up some factor that connects English and Metric liquid volume units. Let's use 1.0059 qts = 1 liter
Start with what you know and cancel units as necessary to get to what you want. All the labeled fractions you multiply by have the numerator and denominator equal so that you multiply by "one" and don't change the measurement when you change units:
271.7 gal/min (qt/gal)(liters/qt)(cl/liter)(min/hour)(hour/day)(day/week) = cl/week
Multiply through once you have all the numbers in place so that the top and bottom of the fractions are equal.
The first fraction is 4 qt/ 1 gal, the second is 1 liter/ 1.0059 qts, etc.
