given an AP is required of all integers between 101 and 999 which are even

To find: the sum of all even integers between 101 and 999

So, the sequence is 102, 104, 106….998

It is an AP whose first term is 102 and d is 2

Hence the sum is given by the formula

Now for the finding number of terms, the formula is

n = 449

Substituting n is the sum formula we get

s = 246950