Question

The Sum of first N consecutive odd integers is N^2. What is the sum of all odd integers between 13 and 39 inclusive.

A. 351
B. 364
C. 410
D. 424
E. 450

Answer 1

\[39^2-11^2\]

Answer 2

i.e. add from 1 to 39, and subtract from1 to 11

Answer 3

it wont be 39^2 - 11^2 ,,by N we mean the nth odd term..
so out ans should be

20^2 - 6^2

Answer 4

@satellite73

Answer 5

yeah, it will becomes 20^2-6^2 = (20+6)(20-6) = 26 * 14
:)