Which quantity is proportional to 1/5?Check all that apply

Renita analyzed two dot plots showing the snowfall during the winter months for city a and for city b. she found that the median snowfall is 5 inches less in city a than in city b. the mean snowfall is about 2 inches less in city a than in city b. which explains why there is a difference in the measures of center for the sets of data?

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What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9