Question

The length of a rectangle is twice its width the perimiter is 60 ft find its area

Answer 1

Hello,

let's assume a=the length and b the width.

$\left\{\begin{array}{ccc}a&=&2*b\\2(a+b)&=&60\\\end{array}\right.\\\\\\\left\{\begin{array}{ccc}a&=&2*b\\a+b&=&30\\\end{array}\right.\\\\\\\left\{\begin{array}{ccc}a&=&2*b\\3b&=&30\\\end{array}\right.\\\\\\\left\{\begin{array}{ccc}b&=&10\\a&=&20\\\end{array}\right.\\\\\\Area=10*20=200\ (ft^2)$