a)Louisa : c - 0,15*c
New expression : 100% * c - 15% * c = 85% * c
Comparison : c - 0,15*c and 85%*c : the expressions are basically the same, except Louisa's expression is in decimal numbers, and the new expression is in percentage.
Louisa's expression is represented like substraction with decimal numbers, and the new expression is in percentage and it means the total amount directly.
b) width = w = 16 feet
lenght = l = 16 feet + 4%*16 = 16 + 0,04 * 16 = 16 * (1+0,04) = 16 * 1,04 = 16,64 feet
the area of the new room = w * l = 16 * 16,64 = 266,24 square feet
