Question

the perimeter of a rectangle is 36 yards the width is 18 yards less than twice the length find the length and the width of the rectangle

Answer 1

Let Length = L
then 
W=width = 2*L-18
Perimeter = 2(W+L)=2(2L-18+L)=36
divide by 2
3L-18=36/2=18
3L=18+18=36
L=36/3=12 => W=2*L-18=2*12-18=6
=>
Length = 12, Width=6

Check: 2(12+6)=2(18)=36 =perimeter !  checks!