Question

The ratio of rainy days to non rainy days was 2 to 3. How many of the 30 days in April were rainy?

Answer 1

(30/(2+3))2=12

So there were 12 rainy days in April.

check...

If there are 2:3, rainy to non-rainy there are 5 equal parts of magnitude:  30/5=6

So each part is equal to 6.  So 6*2=12 rainy days and 6*3=18 non-rainy days.

Answer 2

20 days were rainy.

2:3=x:30
2/3=x/30
x=20