The cake measures 10 inches by 15 inches. If pieces are 2.5 inches long and wide (they are square and equal) then 6 pieces will be cut along the length.
15/ 2.5 = 6
And 4 pieces will be cut along the width.
10/ 2.5 = 4
All together when the entire cake is cut, there will be 4*6 = 24 squares 2.5 inch long pieces.
