Question

A mover packs books, CDs, and DVDs into a moving box. If the box contains 6.5 kg of books, 1.5 kg of CDs, and 2.0 kg of DVDs, what is the percent by mass of each object in the box?

Answer 1

%M1 = 6.5 / 10 x 100 = 65%

%M2 = 1.5/10 x 100 = 15%

%M3 = 2.0/10 x 100 = 20%

Answer 2

Given: 
M1 = 6.5 kg of books
M2 = 1.5 kg of CDs
M3 = 2.0 kg of DVDs

Required: percent by mass of each object

Solution:
First, we calculate the total mass.

M = 6.5 kg + 1.5 kg + 2.0 kg =  10 kg

Percent by mass is calculated by getting the ration of the mass of an object and the total mass multiplied by 100 to get the percent.

%M1 = 6.5 / 10 x 100 = 65%
%M2 = 1.5/10 x 100 = 15%
%M3 = 2.0/10 x 100 = 20%