In Chicago it snowed 65% of the day’s in January. How many days did it NOT snow in January?

In Chicago it snowed 65% of the day’s in January. How many days did it NOT snow in January?

If it snowed 65% of the days in January, then it did NOT snow 100% - 65% = 35% of the days in January.

Since there are 31 days in January, we have:
35% * 31 = 10.85 days in January. So we round down up to 11 days.