Question 193334
Perimeter  of  rectangle  is  2*length+2*width
but  l=3w
p=2l+2w=2(3w)+2w=8w,,,but  given  =240
therefore  w=240/8,  =30

and  l=3w=3*30=90
check
Per=2(30)+2(90)=60+180=240,,,,ok