Explanation:
The dimensions of a standard backpack is 30cm x 30cm x 40cm
The mass of an average student is 70 kg
We know that, the density of gold is 19.3 g/cm³.
Let m be the mass of the backpack. So,

An average student has a mass of 70 kg. If we compare the mass of student and mass of backpack, we find that the backpack is 10 times of the mass of the student.
Answer:
76.875 cm3
<h2>
Explanation:</h2>
Since: Density = 
Then: Volume = 
The mass of the box = 246g
and the density = 3.2 g/cm3
Then: The volume = 
= 76.875 cm3
(20*1000)÷(molecular weight of H3po4*50)
In 1854, Cyrus West Field conceived the idea of the telegraph cable and secured a charter to lay a well-insulated line across the floor of the Atlantic Ocean. Obtaining the aid of British and American naval ships, he made four unsuccessful attempts, beginning in 1857.