prove that

Total quantity obtained from the given three colours $=192+228+180=600$

Also, $\quad 600=100 \%$

or $1=\frac{100}{600} \%=\frac{1}{6} \%$

or $192=\frac{1}{6} \times 192=32 \%$

or $228=\frac{1}{6} \times 228=38 \%$

or $180=\frac{1}{6} \times 180=30 \%$