If it rained 3 days out of 20 days, on what percent of days did it rain?

Number of days it rained = 3 days

Total number of days within which it rained for 3 days = 20 days.

So the percentage of days it rained = (3*100) / 20

= 300/20

= 15.

So in total it rained for 15% of the days.