Answer :
[tex]x-\ number\ of\ boys\\\\y-\ number\ of\ girls\\\\
z-\ all\ students\\\\
y=\frac{3}{4}z\\
x=\frac{1}{4}z\\\\
\frac{1}{3}y+\frac{1}{2}x=330\\\\
\frac{1}{3}(\frac{3}{4}z)+\frac{1}{2}(\frac{1}{4}z)=330\\\\
\frac{3}{12}z+\frac{1}{8}z=330\\\\
\frac{1}{4}z+\frac{1}{8}z=330\ \ \ | common\ denominator\\\\
\frac{2}{8}z+\frac{1}{8}z=330\\\\
\frac{3}{8}z=330\ \ \ | multiply\ by\ 8\\\\
3z=2640\ \ \ | divide\ by\ 3\\\\z=880\\\\
Total\ number\ of\ students\ is\ equal\ to\ 880.
[/tex]
