Answer:
let the width of the rectangle be x inches
then the length would be 2x-6
as perimeter =2(l+b)
putting values in formula
perimeter = 2(2x-6+x)
p= 6x-12 but as perimeter p=54inches so
54=6x-12
54+12=6x
66=6x
x=66/6
x=11 inches
width is 11inches and length is 2x-6= 2(11)-6=22-6=16 inches
Explanation: