percentage...

1.
let B is 1, then A = 1.2
i.e. (1.2 - 1)/1.2 x 100%
Then B is 16.67% less than A

2.
Let D is 1, then C is 0.8
i.e. (1 - 0.8)/0.8
Then D is 25% greater than C

1.If A is 20% greater than B, then what percent B less than A?
A(1+20%)=B
A=5B/6
A is greater than B 17%

2. If C is 20% less than D, then what percent D greater than C?
C(1-25%)=D
C=4D/3
Cis greater D 33%

B is(1-20%)
D is(1+20%)