A is 20% more than B, and B is 50% less than C. If C is 25% more than D, then A is what percentage less than D?

25%

20% = $\frac{1}{5}$

50% =  $\frac{1}{2}$

25% =  $\frac{1}{4}$

                A     :     D

20% ⇒      6     :     5     

100% ⇒    1     :     2

25% ⇒      5     :     4   

    6 × 1 × 5     :     5 × 2 × 4

           3          :          4           = 1 (difference)                       

A is = $\frac{1}{4}$ × 100 = 25 % less than D.