The correct option is D 1 : 8
Before we find the ratio, it is necessary to make sure that the width and the length are in the same unit. Either convert both of them into centimetres, or both of them into metres. Thus, in centimetres, we have the length of the picture to be 180 and the width to be 60. Also, the perimeter of the picture is 2×(60+180)=480 cm. Thus, the ratio of the width of picture to its perimeter is
60480=18