If A is 20% taller than B, by what percent is B shorter than A?
a. 20%                         b. 25%                         c. 16.66%        d. None

A = 1.2 B
=> B = A/1.2
 => 0.8333A => 16.66%.
(OR) Decrease from 1.2 to 1 => 16.66%.