Question

pat's income is 20% more than Adam how much percentage is Adam's income less than pat's

Answer 1

The actual solution is trivial.

let pat be a and adam be b

A = 20% more than B

100 % of A = 20% of B + 100% of B

100 % of A = 120% of B

(100/120)% of A = 1% of B

(100*100/120)% of A =100 % of B

~83.33% of A = 100 % of B

So, B is ~(100 - 83.33 = ) 16.67% less than A.

Of course, I'm assuming here that when you said "A is 20% more than B," you meant A is 20% more that B with respect to B, and so on.