nravi4 wrote:
The sum of any evenly distributed numbers = (Total numbers in the distribution) * ((first number + lastnumber)/2)
Example1: The sum of first 5 integers (1, 2, 3, 4, 5) is:
(5)*((1+5)/2) = 5*3 = 15
Example2: The sum of first 5 odd integers (1 3 5 7 9) is:
5*((1+9)/2) = 5 * 5 = 25
Example3: The sum of first 6 odd integers ( 1 3 5 7 9 11) is: 6 * 6 = 36
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What's given in the problem is the sum of 1 to k odd consecutive integers is: 441 (i.e: 7*7*3*3, i.e, 21*21)
===> 21 * (( 1+k)/2) = 21 * 21
===> (1+k)/2 = 21
===> k = 42 - 1 = 41
Cheers!
Ravi
keep finding stuff i dont understand in explanations and for the first time i will try to point out something with the risk of looking stupi.....
whilst your examples are very good, why do you multiply by 21? I get that 441=21*21 but how do you know that
(Total numbers in the distribution) = 21?