$(100\%+42\%)xA=15194\phantom{\rule{0ex}{0ex}}A=15194\times \frac{100}{142}=10700\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\mathrm{Increase}\mathrm{in}A\left(\mathrm{shaded}\right)=1519410700\phantom{\rule{0ex}{0ex}}=4494(\mathrm{ans},a)\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\mathrm{Decrease}\mathrm{in}C=269+4494\phantom{\rule{0ex}{0ex}}=4763\phantom{\rule{0ex}{0ex}}\%\mathrm{of}\mathrm{decrease}\mathrm{in}C=\frac{\mathrm{Decrease}\mathrm{in}C}{\mathrm{Total}C}\phantom{\rule{0ex}{0ex}}=\frac{4763}{4763+8827}\times 100\%\phantom{\rule{0ex}{0ex}}=35.1\%(\mathrm{ans},b)$ 


