My Sol - Please could someone tell me if this is totally valid or not, I have outlined my thought process below
1/100 + 2/100 + 3/100 +...+N/100 = 100N
We know that the Sum of N numbers must = 100N
The Sum of N numbers = Average of N numbers * N (number of terms)
100N = Average * N
This means that our Average value must be 100
This can only be achieved when the Average value is such that N/100 = 100, i.e, N = 10000
If you were to multiply the LHS of the sum by 100, you would have an evenly spaced set of consecutive integers.
We know that the mean = median with such sets, so that means that the average value of 10000 must be the median = mean
Via a property of evenly spaced sets, we know that the average of the first and last term = the mean = the median, so that means (N/100 + 1/100) / 2 = 100
So N-1/100 = 200
so N-1 = 20000
Thus, N = 19999