Answer:
31, 33, 35
Explanation:
 
Let 2n+1 be the first odd number. What will the next one be? Add two: 
Let 2n+3 be the next odd number. Again, what is the next one? Add two: 
Let 2n+5 be the third odd number. 
 
The sum of those three numbers must be 99. You don't have to have the parenthesis here, but I think they help clarify where everything comes from. 
 
(2n+1) + (2n+3) + (2n+5) = 99 
 
Add like terms, and solve for n: 
 
6n + 9 = 99 
6n = 90 
n = 15 
 
The three odd numbers we want are: 
2(15)+1 = 31 
2(15)+3 = 33 
2(15)+5 = 35 
 
Double check: 31+33+35 = 99?