Question

"A rectangular painting measures 12 inches by 16 inches and is surrounded by a frame of uniform width around the four edges. The perimeter of the rectangle formed by the painting and its frame is 72 inches. Determine the width of the frame.\"

Answer 1

Area of this rectangular painting=lenght x width.
Data:
lenght=16 in.
width=12 in.

Area (rectangular painting)=16 in * 12 in=192 in².

x=width of the frame.
lenght of the frame=16+2x
width of the frame=12+2x

Perimeter of the painting and its frame=2(16+2x)+2(12+2x)

We can suggest this equation:
2(16+2x)+2(12+2x)=72
32+4x+24+4x=72
4x+4x=72-32-24
8x=16
x=16/8
x=2

Answer: the width of the frame is 2 in.

Answer 2

it is a simple one so need to think hard
uniform width of x so the actual perimeter is 
2(12 + x + 16 + x) 
2(28 + 2x) = 72 
28 + 2x = 36 
2x = 8 
x = 4 inches