Explanation

Here we need sum of 2,4,6,……..,98(between 1 and 100)

Now here First term = 2 difference= 2, n = 50

So now sum of these terms = n/2(2a+(n-1)d)

= 49/2(2*2+(50–1)2)

= 49/2(4+(49)*2)

= 49/2(4+98)

= 49/2(102)

= 49*51

=2550