$\mathrm{Total}=7U\phantom{\rule{0ex}{0ex}}=7\times 100\phantom{\rule{0ex}{0ex}}=700\left(\mathrm{ans}\right)$ 



$\mathrm{Girls}1\frac{2}{7}=\frac{5}{7}\phantom{\rule{0ex}{0ex}}(\frac{5}{7}\frac{2}{7})\left(\mathrm{Pupils}\right)=300\phantom{\rule{0ex}{0ex}}\mathrm{Pupils}=300\times \frac{7}{3}\phantom{\rule{0ex}{0ex}}=700\left(\mathrm{ans}\right)$ 


