Let's break it down:
a% of b = (a/100) × b
b% of a = (b/100) × a
The sum of these two expressions:
(a/100) × b + (b/100) × a
= (ab/100) + (ab/100)
= 2ab/100
To find the percentage of ab:
(2ab/100) / ab × 100%
= 2%
So, the sum of a% of b and b% of a is 2% of ab.