what is the volume of 3.85x10^24 molecules of AMmmonium Bromide? please explain I'm confused

I am too. Ammonium bromide is a solid and without the density the volume can't be calculated. Since you know 6.022E23 molecules is one (1) mol, you know you have 3.85E24/6.022E23 = ? moles.

Then g NH4Br = mols x molar mass = ?
Finally, density = mass x volume. You know mass and if you know the density you can calculate the volume.