The given information yields the ratio 3 blueberry : 2 pumpkin : 1 bran.
We need to multiply this by 10 to get 20 pumpkin in the ratio. Doing so gives us 30 blueberry : 20 pumpkin : 10 bran. Adding all of the muffins together gives us 60 muffins. So, 60 muffins is the answer.