Question

If it rained on 3 days ut of 20 days on what percent of the days did it rain

Answer 1

It rained 15% of 20 days.

Answer 2

Let's set up a proportion.
3/20=x/100
Because 20*5=100, you can determine x by multiplying the numerator by 5 as well.
3*5=15
x=15
15%