Find the ratio of black cell phone covers sold to the total number of cell phone covers sold last week. then explain its meaning.

color | number of cell phone covers sold
green | 5
silver | 6
red | 3
black | 4

To find the ratio of the black cell phone covers sold to the total number of cell phones, just merely divide their corresponding quantities. From the given table, you can obtain that there are 4 black cell phone covers sold. The total number of cell phones would be the sum of the green, silver, red and black cell phone covers. That would be equal to: 5 + 6 + 3 + 4 = 18. Therefore, the ratio is equal to

Ratio = 4/18 = 2/9

This ratio can be interpreted ways. If we want to see it in the perspective of statistics, that means that 2.9 or 22.2% of the total sales are from the black covers. If you want to use the ratio as a benchmark to similar data points, you can determine the number of black covers sold for any number of total covers. For example, if there are a total of 100 cell phone covers, by ratio and proportion, there would be 22 black cell phone covers among that group.