Correct Answer - 1000 sq.cm
Volume of the cube =`("edge"^(3))=(2.5^(3))` cu cm
Area of the base of rectangular solid =12.5`xx`0.25 sq.cm
Height of solid =`("volume")/("area of base")=(2.5^(3))/(1.25xx0.25)`=50cm
surface area of the cube =`6xx("edge")^(2)=6xx(2.5)^(2)=37.5` sq.cm
Surface area of the solid =2(lb+bh+hl)=`2(50xx1.25+1.25xx0.25+50xx0.25)`
Gain in surface area =150.625-37.50=113.125 sq.cm