You decided to gather some information for how many days it rained over a period of time. You observed that it rained on 17 days and it did not rain on 13 days. Write a ratio comparing the number of days it rained to the total days you were collecting data.

The correct answer is 17: 30

Explanation:

The purpose of a ratio is to express the relationship between two elements in terms of quantities. For example, if there are 5 oranges and 4 lemons the ratio is 5 to 4. Additionally, this relationship between the quantities of two different things can be expressed as a fraction, by using a colon (:) or by using the word "to." In the last two cases, the colon or word "to" separate the two amounts compared.

In the case presented, the total of days observed was 30 days (17 days with rain + 13 days with no rain) and the ratio of rainy days to the total of days can be expressed as 17:30, or as 17 to 30, considering there were 17 rainy days out of a total of 30 days.