Explanation:

To find out how much B's income is less than A's income as a percentage, we need to understand the given information and calculate the difference.

Given:
A's income is 10% more than B's income.

Let's assume B's income as x.
So, A's income will be 10% more than x, which can be calculated as:
A's income = x + (10/100)x
= x + 0.1x
= 1.1x

Calculating the percentage difference:
The percentage difference is calculated by finding the difference between the two values and expressing it as a percentage of one of the values.

Difference = A's income - B's income
= 1.1x - x
= 0.1x

Percentage difference = (Difference / B's income) * 100
= (0.1x / x) * 100
= 10%

Therefore, B's income is 10% less than A's income.

Explanation of the given answer (9.09%):
The answer given (9.09%) seems to be a rounding error or a slight approximation. The exact percentage difference between B's income and A's income, as calculated above, is 10%. It is important to note that this is an exact value, and any variation from 10% would be due to rounding or approximation.

It is possible that the answer provided (9.09%) is rounded down from the exact value of 10%. Rounding down to the nearest decimal place could result in 9.09%. However, this may not be an accurate representation of the exact percentage difference.

In summary, the exact percentage difference between B's income and A's income is 10%. The provided answer of 9.09% may be a rounded or approximate value.