Question

if A's income is 10% less than that of B by what percent is B's income more than a

Answer 1

Let Income of B = x
Then Income of A = 0.9x

Let the percentage by which B income is more than A = y.
B = A + y% of A
x = 0.9x +y/100*0.9x
x = 0.9x ( 1 + y/100)
1 = 0.9 ( 100 + y) / 100
1000/9 = 100 + y.

1000-900/9 = y
100/9 = y.
Y = 11.1%