The sweater prices have reduced by 80% due to the special.
Step-by-step explanation:
Step 1; Cost before reduction was $30. The cost after reduction was 6$. Cost reduced= cost before reduction - cost after reduction
Cost reduced= $30 - $6 = $24
Step 2; We must find how much of the cost was reduced from the initial cost i.e. how much $6 is to $30. To do this we must convert it into a percentage. We divide the $6 with the $30 to get a value. This value must be multiplied with a 100 to be converted into a percentage.
Cost by which sweater was reduced= 24/30 * 100 = 0.8 * 100 = 80%.
So the price of the sweater was reduced from $30 to $6 which means there was a reduction of 80%.