Question

200 logs are stacked in the following manner: 20 logs in the bottom row, 19 in
the next , above it, 18 in the next, above it and so on. In how many row as are
the 200m logs placed and how may logs are there in the top row?

Answer 1

Sn=n/2(2a+(n-1)d
a=20,Sn=200,d=-1
Solve by yourself

Answer 2

200\20+18+19
200\57
3.58

I hope this is right answer