How many moles are in 4.8 * 1025 atoms of tungsten?

We'll use Avogadro's Number (6.022x10^23) in this equation:

4.8x10^25 atoms W x (1 mole/6.022x10^23 atoms) = 79.7 moles W

The given only contains 2 significant figures, so our answer should also only have 2 sig figs:

80 moles W, OR 8.0 x 10^1 moles W