The Sum of first N consecutive odd integers is N^2. What is the sum of all odd integers between 9 and 39 inclusive.  Choose the correct choice:
A) 351  B) 384  C) 410  D) 424  E) 450

Rationale: "we ' re dealing with a sequence of consecutive odd integers : 9 to 39 , inclusive . we ' re asked for the sum of this group . 1 ) start with the sum of the smallest and the biggest : 9 + 39 = 48 2 ) now look at the ' next smallest ' and the ' next biggest ' : 11 + 37 = 48 now we have proof that there is no middle term . we have 8 bunches of 48 8 ( 48 ) = 384 b"
Answer: B