Answer:
The function
and Bob will make more money by working alone.
Step-by-step explanation:
Bob's income is determined by
Susie's income is 
Bob and Susie were to combine their efforts, their income would be h(x) = f(x) + g(x).
So, 

Their combined income is determines by 
If Bob works for 3 hours alone
So, Bob's income : 


If bob works 3 hours in a team
So, Income : 


Since together their income for 3 hours is $61
So, This amount will be divided in two parts
So, Each will earn amount = 
So, Bob will earn $30.5 working in a team and $31 working alone
So, Bob will make more money by working alone.
Hence the function
and Bob will make more money by working alone.