First find the number of green straws each mat needs: 30 orange straws / 2 orange straws/green straw = 15 green straws
Then find the total number of straws in each mat: 15 straws + 20 straws + 30 straws = <<15+20+30=65>>65 straws
Then multiply that number by the number of mats to find the total number of straws Ginger needs: 65 straws/mat * 10 mats = <<65*10=650>>650 straws
#### 650