- 12. A rectangular sheet of fixed perimeter with sides having their lengths in the ratio 8 : 15 is converted into an open rectangualr box by folding after removing squares of equal area from all 4 - corners. If the total area of removed squares is 100. Then resulting box has maximum volume then the lengths of the sides of the rectangular sheet are a) 24 b) 32 c) 45 d) 60