Question 254299
I just did this for sum  20
n+n+1=16
2n=15
n=7.5
7.5 is not an integer 
I am sure your problem meant to say integer or it wouldn't say consecutive. 
7 and 8 aren't big enough.
So we try 8 and 9 
Sure enough they equal 17

So the answer is 8 the lesser of the two (8 and 9)