Question

On a chessboard, a person places black and white pawns, one in each block. First, white pawns are placed to form an inner solid square. Next the inner square was outlined by another square formed just outside the inner square by placing one black pawn in each empty block. The number of black pawns needed was one less than that of white pawns needed. What was the total number of pawns used?
a) 49
b) 17
c) 31
d) 97