Hello!
To find the density of any object, use the formula: d = m/V.
In this formula, d is the density, m is the mass, and V is the volume.
In the problem, we are given the mass, which is 178 grams, and the volume, which is 13 cm³. With that, we can divide the mass by the volume to get the density.
178 grams / 13 cm³ ≈ 13.69 grams/cm³
Therefore, the density of this book is 13.69 grams/cm³.