Question

a card board box has a mass of 1,800 g. When 4 books of equal mass are put into the box, the filled box has a mass of 9 kg. what is the mass of each book in grams

Answer 1

I divide 7200by 4 and I got 1800

Answer 2

You have an empty box which is 1,800 grams. After you put the books in, it's 9 kilograms. There are 9,000 grams in 9 kilograms, and 1,800 grams were already there before you put the books.. so just do 9,000 - 1,800 which equals 7,200. Then divide 7,200 by 4, because there are 4 books with equal mass.

Explanation: