Sally drinks 6 sodas every 2 days. How many does she drink in one week

As we all know, there are seven days in one week.

To do this we should make a proportion, with numbers of sodas on top and days on bottom. X will be the # of sodas in a week.

6/2 = x/7 < our proportion

Then, we cross multiply

42 = 2x

21 = x

x = 21, or in other words Sally drinks 21 sodas in a week.