[tex]v = 2 \times 2 \times 2 = 8 {cm}^{3} = \frac{8}{ {10}^{6} } {m}^{3} [/tex]
[tex]2500 = \frac{g}{v} [/tex]
[tex]2500 = \frac{g}{ \frac{8}{ {10}^{6} } } [/tex]
[tex]g = 2500 \times \frac{8}{ {10}^{6} } = \frac{20000}{1000000} = \frac{2}{100} = 0.02kg = 20g[/tex]
