Question

if the weight of 12 sheet of thick paper is 40 grams, how many sheets of the same would weight 21/2 kilograms

Answer 1

No.of sheets weighing 40 grams = 12
No.of sheets weighing 1gram = 12/40
No.of sheets weighing 21/2g = (3/10)×(21/2)
=63/20sheets = 21.5/10 = 2.15 sheets

Answer 2

12 thick sheet weight 40 gm
1 sheet weight 40/12 gm

20/6 gm is weight of 1 sheet
1 gm is weight of 6/20 sheets
21000/2 gm is weight of 6/20*21000/2

=0.3*10,500 Pages
=3150 Pages