+12 The odd intergers are arrranged ito sets, each suceeding set continuing from the previous, and containing one more number as follows: {1},{3,5},{7,9,11}, {13,15,17,19},... What is the sum of the numbers in the 22nd set?
Your sets begin:{1},{3,5},{7,9,11},{13,15,17,19}....etc. forming this number of odd terms in total:
(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 =253 odd terms. So, 253 x 2 - 1 =505 - this being the last term of your 22nd set:505 - (21*2) =463 - this being the 1st. term of your 22nd set. So, the 22nd set begins and ends as follows:
{463, 465, 467, 469, 471, 473, 475, 477, 479, 481, 483, 485, 487, 489, 491, 493, 495, 497, 499, 501, 503, 505} =10,648 - Total of the 22nd set.
