Question 315541
Perimeter is the sum of the four sides. Since we have a rectangle, opposite sides have the same length. So two of the sides have length L and the other two are the width W. Perimeter is {{{ P = 2L + 2W =24 }}}. 

Length is twice the width, that is {{{ L = 2 W}}}. Substitute this into the perimeter equation (replace the 2W with L) to get 

{{{ 2L + 2W = 2L + L = 3L = 24 }}}. Thus, dividing by 3 gives {{{L = 8}}}. The length is twice the width, so the width must be 4. 

We have a 8 x 4 rectangle which has an area of 32 square inches. 

Check that this solution works. The perimeter does indeed add up to 24 and the length is twice the width.