if y is 80 % greater than x , than x is what % less than y ?
"let x = 100 so y = 180 we want percentage change . so , ( 100 - 180 ) / 180 = - 44.44 % = 44 4 / 9 % lesser than y . hence option ( d ) ."
multiply(divide(80, add(80, const_100)), const_100)