Electron density with the Hall effect

An aluminum strip of thickness $s=0.10\mathrm{mm}$ carries the current $I=8.0\mathrm{A}$ in a magnetic field $B=1.2\mathrm{T}$ perpendicular to its wide faces, and the Hall voltage $\Delta V_H=3.3\mu \mathrm{V}$ is measured between its edges. Compute the density of the carriers, of charge $-e$.