Question

15 books each of dimension 2 cm×4cm×5cm are stacked on a shelf . What is the height of the stack , if each book occupies 20 sq cm area on the shelf?

Answer 1

The height of the stack is 30 cm.

• The number of books are 15.
• The dimensions of the stack is given as 2cm×4cm×5cm.
• We have to find the height of stack of books.
• The area that the book occupies on the desk is given as 20 sq. cm.
• Area that the book will occupy = length × breadth

Therefore, 4×5 = 20 sq. cm

• The dimensions that length and breadth could be is 4 cm and 5 cm or 5 cm and 4 cm respectively.

• The dimension left is the height of the book.

Therefore, height of one book is 2 cm.

• Now height of the 15 books = 15 × 2 cm = 30 cm.

• Height of the stack of books is 30 cm.