If you're asking how to simplify, then this is how you do it. 
when a power meets another power but in brackets, then you have to multiply the powers. ¼ × 4 would be 1. i simplified 81 to 3⁴.
 
        
        
        
It will take him 16 hours. Hope it helps
        
             
        
        
        
Given conditions are :
In 1980's, a typical middle-income household earned=  $34,757
In 2009, a similar middle-income household earned= $38,550
And we have to find relative increase in income for these households from 1980 to 2009. 
So first we will find the total increase in amounts. 

Relative increase = 
= 10.91% or rounding it off we get approx 11%.
Hence, the answer is 11%.