Originally Posted by
nazz The sum of first N integers is a three digit number with all of its digits equal, what is the value of N?
1,2,3,4,5,6,7……………. Is an arithmetic series
S= n/2[2a + (n-1) d] = n (n +1) / 2
n (n +1) / 2 = 111x
Since sum of first integers is a three digit number with all digits equal
Hence it xxx = 100x +10x +x = 111x.
By trial and taking x=6, and solving for n, n2 +n – 1332 = 0, I will get n=36, is there any other way of solving;
n (n +1) / 2 = mod 111, and getting value of n=36 from this equation?