the original weight is 190 pounds
the new weight is 160 pounds
so the percentage of weight loss is
[tex]=\frac{original\text{ weight - new weight}}{\text{original weight}}\times100[/tex][tex]\begin{gathered} =\frac{190-160}{190}\times100 \\ =\frac{30}{190}\times100 \\ =15.78 \end{gathered}[/tex]so she loss 15.78 per cent of the weight.