Answer:
width = 38.6 cm (approx.)
Explanation:
let the width be x cm, so that the length is 2.5x cm.
Perimeter = 2 (length + width)
2 (length + width) = 270 cm
or, 2 (2½x cm + x cm) = 270 cm
or, 3½x cm = 270/2 = 135 cm
or, x = 270/7 cm = 38.6 cm (approx.)