Mrs Chan baked some muffins. 35 percent of the muffins are chocolate muffins and the rest are banana muffins. She baked a total of 80 muffins. How many banana muffins did she bake?

The number of chocolate muffins baked is 35/100 x 80 = <<35/100*80=28>>28.

Therefore, Mrs Chan baked 80 - 28 = <<80-28=52>>52 banana muffins. Answer: \boxed{52}.