Cyrano starts with a total of 12.5 yogurt cups after buying some new ones. He eats 3.75 cups for lunch and then shares 2/5 of the remaining cups with his family for dinner. How many yogurt cups does he have left after dinner?
Cyrano has 12.5 - 3.75 = <<12.5-3.75=8.75>>8.75 cups of yogurt after lunch.
Then, 8.75 x 2/5 = <<8.75*2/5=3.5>>3.5 cups of yogurt are shared with his family.
Therefore, Cyrano has 8.75 - 3.5 = <<8.75-3.5=5.25>>5.25 yogurt cups left after dinner. Answer: \boxed{5.25}.