A painting with dimensions 10 inches by 14 inches is placed in a picture frame (of constant width), increasing its area to 221 square inches. How many inches is the width of the picture frame?

What do you mean in your question that the frame has a "Constant Width"?? The area of the painting which was 10 x 14 = 140 increased to 221. But, 221 = 17 x 13. So, what is the "constant width" of the frame?? Can't you figure it out?

A painting with dimensions 10 inches by 14 inches is placed in a picture frame (of constant width), increasing its area to 221 square inches. How many inches is the width of the picture frame?