Idon’t understand this at all, if someone could me

Ok,

So what don't you understand. The whole page

Answer is 38.38 g

Explanation;

To find out the mass, we can apply the simple formula,

d = m / v

Where, d is the density of the substance, m is the mass and v is the volume of the substance.

Values of d and v are given as follows;

d = 1.23 g/mL

v = 31.2 mL

m = ?

By applying the formula,

1.23 g/mL = m / 31.2 mL

            m = 1.23 g/mL x 31.2 mL

            m = 38.376 g = 38.38 g