problem on solving for area and mass stuff.?

Question

can somone solve this and explain in general how to do these types of problem?
Q: the aluminum foil on a certain roll has a total area of 18.5 square meter and a mass of 1275g. using a density of 2.7g per cubic centimeter for aluminum, determine the thickness of the alumium in milimeters.

Answer 1

The formula for density = mass/volume or p=m/v where p is rho, a symbol of density.
First solve for volume. Invert: v/m=1/p.
Multiply by m: v=m/p
Volume v = Area (a) * thickness (t)
a*t=m/p
t=m/(a*p)
t=1275g/(18.5 square meter * 2.7g per cubic centimeter )
t= 1275/(18.5*2.7)
t= 25.5255255 g/(m^2*g/cm^3 * 10000 cm^2/1m^2)
t= 25.5255255 g/(g*10000/cm)
t= 25.5255255 g*cm/(g*10000)
t= 0.00255255255 cm
t= 2.55255255 × 10^-5 meters

Answer 2

A=18.5m^2
M=1275g=1.275kg
d=2.7g/cm^3=.0027kg/cm^3*10^6cm^3/m^3=.027*10^6=2700kg/m^3
V=1.275kg/2700kg/m^3=4.722*10^(-4)m^3
A=18.5=V/t=4.722*10^(-4)/t
t=4.722*10(-4)m^3/18.5m^2=2.5526*10^(-5)=.0255mm=