What are Ratios? - Definition & Examples

Dex and Haley both collect hats. Dex has $5$ baseball caps, $2$ bucket hats and $7$ knit beanies. Haley has $3$ caps, $2$ sun hats and $5$ knit beanies. Let's categorize caps, bucket hats and sun hats as summer hats and knit beanies as winter hats. Counting both Dex and Haley's collections, what is the simplified ratio between summer and winter hats?