The Sum of first N consecutive odd integers is N^2. What is the sum of all odd integers between 15 and 41 inclusive. Select.
A) 351 B) 392 C) 410 D) 424 E) 450
We're dealing with a sequence of CONSECUTIVE ODD INTEGERS: 15 to 41, inclusive. We're asked for the SUM of this group.   1) Start with the sum of the smallest and the biggest:   15 + 41= 
<gadget id="calculator">  15 + 41</gadget>
<output>56</output>
56   2) Now look at the 'next smallest' and the 'next biggest': 17 + 39= 
<gadget id="calculator">17 + 39</gadget>
<output>56</output>
56   Now we have proof that there is no middle term. We have 7 bunches of 56.   7(56)= 392   392
<result>B</result>
The Sum of first N consecutive odd integers is N^2. What is the sum of all odd integers between 15 and 41 inclusive.