Question

If the total area of a picture measuring 10 inches by 12 inches plus a matting of uniform width surrounding the picture is 224 square inches, the width of the matting is

A: 2 inches
B: 2 4/11 inches
C: 3 inches
D: 4 inches

Answer 1

let
x-----------> uniform width surrounding the picture

we know that
(10+2x)*(12+2x)=224-----> 120+20x+24x+4x²=224
4x²+44x+120-224=0
4x²+44x-104=0

using a graph tool-----> to resolve the second order equation
see the attached figure

the solution is
x=2 in

the answer is
2 inches