Generally for such if nothing mentioned we take natural numbers (because there isn’t a first even integer…goes from – infinity to + infinity) Reply
CAT-holics 
In Q3 Shouldn’t the answer be 3775?
Yes indeed, a typo 🙂 I’ll correct it soon.
regards
J
Sir in the 4th question why didn’t we took “a” as zero?
also in the last question did we work on the second level series i.e 12,20,28 with d=8?
Could but that would be lengthy. Just used summation formula for squares…
Generally for such if nothing mentioned we take natural numbers (because there isn’t a first even integer…goes from – infinity to + infinity)